ACMR ACM Research Inc

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ACM Research, Inc. (“ACM” or “ACM Research”) and its subsidiaries (collectively with ACM, the “Company”) develop, manufacture and sell capital equipment to the global semiconductor industry.

ACM was incorporated in California in 1998, and it initially focused on developing tools for manufacturing process steps involving the integration of ultra low-K materials and copper. The Company’s early efforts focused on stress-free copper-polishing technology, and it sold tools based on that technology in the early 2000s.

In 2006, the Company established its operational center in Shanghai in the People’s Republic of China (“mainland China”), where it operates through ACM’s subsidiary, ACM Research (Shanghai), Inc. (“ACM Shanghai”). ACM Shanghai was formed to help establish and build relationships with integrated circuit manufacturers in mainland China, and the Company initially financed its Shanghai operations in part through sales of non-controlling equity interests in ACM Shanghai.

In 2007, the Company began to focus its development efforts on single-wafer wet-cleaning solutions for the front-end chip fabrication process. The Company introduced its SAPS megasonic technology, which can be applied in wet wafer cleaning at numerous steps during the chip fabrication process, in 2009. It introduced its TEBO technology, which can be applied at numerous steps during the fabrication of small node two-dimensional conventional and three-dimensional patterned wafers, in March 2016. The Company has designed its equipment models for SAPS and TEBO solutions using a modular configuration that enables it to create a wet-cleaning tool meeting the specific requirements of a customer, while using pre-existing designs for chamber, electrical, chemical delivery and other modules. In 2018, the Company introduced its Ultra-C Tahoe wafer cleaning tool, which can deliver high cleaning performance with significantly less sulfuric acid than typically consumed by conventional high-temperature single-wafer cleaning tools. In 2020, the Company introduced a range of semi-critical cleaning systems, extending its products to support additional less demanding but still important production steps to semiconductor manufacturers.

Based on its electro-chemical plating (“ECP”) technology, the Company introduced in 2019 its Ultra ECP ap, or “Advanced Packaging,” tool for bumping, or applying copper, tin and nickel to semiconductor wafers at the die-level, and its Ultra ECP map, or “Multi-Anode Partial Plating,” tool to deliver advanced electrochemical copper plating for copper interconnect applications in front-end wafer fabrication processes. In 2022, the Company added two major new product categories with the introduction of the Ultra Pmax™ PECVD and Ultra Track tools. The Company also offers a range of custom-made equipment, including cleaning, coaters and developers, to back-end wafer assembly and packaging factories, principally in mainland China.

In November 2016, ACM re-domesticated from California to Delaware pursuant to a merger in which ACM Research, Inc., a California corporation, was merged into a newly formed, wholly-owned Delaware subsidiary, also named ACM Research, Inc.

In November 2021, ACM Shanghai completed its STAR Listing and STAR IPO and its shares began trading on the STAR Market. In the STAR IPO, ACM Shanghai issued 43,355,753 shares, representing 10% of the total 433,557,100 shares outstanding after the issuance. The shares were issued at a public offering price of RMB 85.00 per share, and the net proceeds of the STAR IPO, after issuance costs, totaled $545,512. Upon completion of the STAR IPO, ACM owned 82.5% of the outstanding ACM Shanghai shares. However, in May 2023, ACM's ownership declined to 82.1% due to the exercise of 2,150,309 stock options related to ACM Shanghai shares.

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The Company has direct or indirect interests in the following subsidiaries:

									Effective interest held as at
Name of subsidiaries			Place and date of incorporation			Principal Activities			March 31, 2024			December 31, 2023
ACM Research (Shanghai), Inc. ("ACM Shanghai")			Mainland China, May 2005			Principal operating subsidiary			82.1		%	82.1		%
ACM Research (Wuxi), Inc. ("ACM Wuxi")			Mainland China, July 2011			Sales and services			82.1		%	82.1		%
CleanChip Technologies Limited ("CleanChip")			Hong Kong, June 2017			Trading partner between ACM Shanghai and its customers			82.1		%	82.1		%
ACM Research Korea CO., LTD.			Korea, December 2017			Sales, marketing, R&D, production			82.1		%	82.1		%
ACM Research ( Lingang), Inc. ("ACM Lingang") (1)			Mainland China, March 2019			Management of production activities			82.1		%	82.1		%
ACM Research (CA), Inc. ("ACM California")			USA, April 2019			Procurement for ACM Shanghai			82.1		%	82.1		%
ACM Research (Cayman), Inc.			Cayman Islands, April 2019			Administrative function (inactive)			100.0		%	100.0		%
ACM Research (Singapore) PTE. Ltd. ("ACM Singapore")			Singapore, August 2021			Sales, marketing, business development			100.0		%	100.0		%
ACM Research (Beijing), Inc. ("ACM Beijing")			Mainland China, February 2022			Sales, marketing, business development			82.1		%	82.1		%
Hanguk ACM CO., LTD			Korea, March 2022			Sales, services, business development			100.0		%	100.0		%
Yusheng Micro Semiconductor (Shanghai) Co., Ltd.			Mainland China, June 2023			Business development			82.1		%	82.1		%
ACM-Wooil Microelectronics (Shanghai) Co., Ltd.			Mainland China, June 2023			Component development and production			59.4		%	59.4		%

(1) ACM Research (Lingang) Inc. is the English name referred to by its Chinese language name Shengwei Research (Shanghai), Inc., or ACM Shengwei in prior filings. ACM Research (Lingang), Inc. and Shengwei Research (Shanghai), Inc. refer to the same entity.

Basis of Presentation and Principles of Consolidation

The Company’s condensed consolidated financial statements include the accounts of ACM and its subsidiaries. ACM’s subsidiaries are those entities in which ACM, directly or indirectly, controls a majority of the voting power. All significant intercompany transactions and balances have been eliminated upon consolidation.

The accompanying condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and the rules and regulations of the Securities and Exchange Commission (the “SEC”) for reporting on Form 10-Q. Accordingly, they do not include all the information and footnotes required by GAAP for complete financial statements. The accompanying condensed consolidated financial statements should be read in conjunction with the historical consolidated financial statements of the

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Company for the year ended December 31, 2023 included in ACM’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023.

The accompanying condensed consolidated financial statements are unaudited. In the opinion of management, these unaudited condensed consolidated financial statements of the Company reflect all adjustments that are necessary for a fair presentation of the Company’s financial position and results of operations. Such adjustments are of a normal recurring nature, unless otherwise noted. The balance sheet as of March 31, 2024 and the results of operations for the three months ended March 31, 2024 are not necessarily indicative of the results to be expected for any future period.

Use of Estimates

The preparation of the condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the balance sheet date and the reported revenues and expenses during the reported period in the condensed consolidated financial statements and accompanying notes. The Company’s significant accounting estimates and assumptions include, but are not limited to, those used for revenue recognition and deferred revenue, the valuation and recognition of fair value of certain short-term investments and long-term investments, stock-based compensation arrangements, realization of deferred tax assets, assessment for impairment of long-lived assets and long-term investments, allowance for credit losses, inventory valuation, useful lives of property, plant and equipment and useful lives of intangible assets.

Management evaluates these estimates and assumptions on a regular basis. Actual results could differ from those estimates and assumptions.

Cash and Cash Equivalents

Cash and cash equivalents consist of cash on hand, bank deposits that are unrestricted as to withdrawal and use, and highly liquid investments with an original maturity date of three months or less at the date of purchase. At times, cash deposits may exceed government-insured limits.

The following table presents cash and cash equivalents, according to jurisdiction as of March 31, 2024 and December 31, 2023:

			March 31, 2024						December 31, 2023
United States			$	45,179					$	43,614
Mainland China			101,590						70,418
China Hong Kong			63,401						64,057
Korea			1,068						3,934
Singapore			67						67
Total			$	211,305					$	182,090

The amounts in mainland China do not include short-term and long-term time deposits which totaled $76,205 and $121,342 at March 31, 2024 and December 31, 2023, respectively.

Cash held in the U.S. exceeds the Federal Deposit Insurance Corporation insurance limits and is subject to risk of loss. No losses have been experienced to date.

Cash amounts held in mainland China are subject to a series of risk control regulatory standards from mainland China bank regulatory authorities. ACM’s subsidiaries in mainland China are required to obtain approval from the State Administration of Foreign Exchange (“SAFE”) to transfer funds into or out of mainland China. SAFE requires a valid agreement to approve the transfers, which are processed through a bank. Other than these mainland China foreign exchange restrictions, ACM’s subsidiaries in mainland China are not subject to any restrictions and limitations on its ability to transfer funds to

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ACM or among our other subsidiaries. However, cash held in mainland China does exceed applicable insurance limits and is subject to risk of loss, although no such losses have been experienced to date.

ACM California periodically procures goods and services on behalf of ACM Shanghai. For these transactions, ACM Shanghai makes cash payments to ACM California in accordance with applicable transfer pricing arrangements. For the three months ended March 31, 2024 and 2023, cash payments from ACM Shanghai to ACM California for the procurement of goods and services was $4,648 and $10,931, respectively. ACM California periodically borrows funds for working capital advances from its direct parent, CleanChip. ACM California repays or renews these intercompany loans in accordance with their terms.

For sales through CleanChip and ACM Research, a certain amount of sales or advanced payments from customers is repatriated back to ACM Shanghai in accordance with applicable transfer pricing arrangements in the ordinary course of business. ACM Research provides services to certain customers located in the U.S., Europe and other regions outside of mainland China to support the evaluation of first tools and provide support for tools under warranty on behalf of ACM Shanghai. For these transactions, ACM Shanghai makes cash payments to ACM Research in accordance with applicable transfer pricing arrangements.

Amounts held in Korea exceed the Korea Deposit Insurance Corporation insurance limits and is subject to risk of loss. No losses have been experienced to date. There is no additional restriction for the transfer of cash from bank accounts in the U.S., Korea, Singapore and Hong Kong.

For the three months ended March 31, 2024 and 2023, with the exception of sales and services-related transfer-pricing payments in the ordinary course of business, no transfers, or distributions have been made between ACM Research and its subsidiaries, including ACM Shanghai, or to holders of ACM Research Class A common stock.

Time Deposits

Time deposits are deposited with banks in mainland China with fixed terms and interest rates which cannot be withdrawn before maturity, and are presented as short-term deposits and long-term deposits in the condensed consolidated financial statements based on their expected time of collection. They are also subject to the risk control regulatory standards described above upon maturity.

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At March 31, 2024 and December 31, 2023, time deposits consisted of the following:

			March 31, 2024			December 31, 2023
Deposit in China Merchant Bank which matured on January 29, 2024 with an annual interest rate of 2.85%			$	—		$	29,797
Deposit in Bank of Ningbo which matured on February 17, 2024 with an annual interest rate of 2.85%			$	—		$	44,630
Deposit in Shanghai Pudong Development Bank which matures on October 20, 2025 with an annual interest rate of 3.10%			$	7,361		$	7,322
Deposit in Shanghai Pudong Development Bank which matures on November 14, 2025 with an annual interest rate of 3.10%			$	4,407		$	7,307
Deposit in Shanghai Pudong Development Bank which matures on December 8, 2025 with an annual interest rate of 3.10%			$	—		$	4,376
Deposit in Shanghai Pudong Development Bank which matures on December 15, 2025 with an annual interest rate of 3.10%			$	1,465		$	4,373
Deposit in Shanghai Pudong Development Bank which matures on December 30, 2025 with an annual interest rate of 3.10%			$	—		$	2,912
Deposit in China Industrial Bank which matures on January 3, 2026 with an annual interest rate of 3.15%			$	14,608		$	14,528
Deposit in China Everbright Bank which matures on December 5, 2024 with an annual interest rate of 5.38%			$	—		$	3,079
Deposit in China Everbright Bank which matures on May 22, 2024 with an annual interest rate of 5.28%			$	3,057		$	3,018
Deposit in China Everbright Bank which matured on April 5, 2024 with an annual interest rate of 5.33%			$	3,037		$	—
Deposit in China Merchant Bank, Lujiazui Branch which matures on May 27, 2024 with an annual interest rate of 1.85%			$	14,090		$	—
Deposit in China Merchant Bank, Huaihai Branch which matures on May 27, 2024 with an annual interest rate of 1.85%			$	14,090		$	—
Deposit in Bank of Ningbo which matures on September 11, 2024 with an annual interest rate of 1.50%			$	14,090		$	—
			$	76,205		$	121,342

For the three months ended March 31, 2024 and 2023, interest income related to time deposits was $624 and $975, respectively.

Financial Instruments

The Company periodically invests in equity securities, and maintains an investment portfolio of various holdings, types, and maturities. For equity investments that do not have a readily determinable fair value, the Company classified them as long-term investments, and records them using either: 1) the measurement alternative which measures the equity investments at cost minus impairment, if any, plus or minus changes resulting from qualifying observable price changes; or 2) the equity method whereby the Company recognizes its proportional share of the income or loss from the equity method investment. The equity method is utilized when the equity investments are common stock or in substance common stock, and the Company does not have the ability to control the investee but is deemed to have the ability to exercise significant influence over the investee’s operating or financial policies. For equity investments that have a readily determinable fair value, the Company classified them as short-term investments, and records them at fair market value on a recurring basis based upon quoted market prices. Realized and unrealized gains and losses resulting from application of the measurement alternative, the impact of the application of the equity method to the Company’s equity investments, and recognition of

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changes in fair market value, as applicable, are recognized as non-operating income (expenses), net in the condensed consolidated statements of comprehensive income.

The Company defines fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, the Company considers the principal or most advantageous market in which it would transact, and it considers assumptions that market participants would use when pricing the asset or liability.

A fair value hierarchy has been established that prioritizes the inputs to valuation techniques used to measure fair value. The level of an asset or liability in the hierarchy is based on the lowest level of input that is significant to the fair value measurement. Assets and liabilities carried at fair value are classified and disclosed in one of the following three categories:

Level 1: Valuations based on quoted prices in active markets for identical assets or liabilities with sufficient volume and frequency of transactions.

Level 2: Valuations based on observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active for identical assets or liabilities, or model-derived valuations techniques for which all significant inputs are observable in the market or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3: Valuations based on unobservable inputs to the valuation methodology that are significant to the measurement of fair value of assets or liabilities and based on non-binding, broker-provided price quotes and may not have been corroborated by observable market data.

The Company’s primary financial instruments include its cash, cash equivalents, short term and long term deposits, restricted cash, short-term and long-term investments, other receivables, accounts receivable, accounts payable, and short-term and long-term borrowings. The estimated fair value of cash and cash equivalents, short-term time deposits, accounts receivable, other receivables, accounts payable, and short-term borrowings approximates their carrying value due to the short period of time to their maturities.

All transfers between fair value hierarchy levels are recognized by the Company at the end of each reporting period. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value

measurement in its entirety, requires judgment and considers factors specific to the investment. The inputs or methodology

used for valuing financial instruments are not necessarily an indication of the risks associated with investment in those instruments.

Assets and liabilities measured at fair value on a recurring basis:

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			Quoted Prices in Active Markets for Identical Liabilities (Level 1)			Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)			Total
As of March 31, 2024:
Assets
Cash and cash equivalents			$	36,509		$	—		$	—		$	36,509
Short-term investments			18,648			—			—			18,648
			$	55,157		$	—		$	—		$	55,157
As of December 31, 2023:
Assets
Cash and cash equivalents			$	37,518		$	—		$	—		$	37,518
Short-term investments			21,312			—			—			21,312
			$	58,830		$	—		$	—		$	58,830

Assets and liabilities measured at fair value on a non-recurring basis:

			Quoted Prices in Active Markets for Identical Liabilities (Level 1)						Significant Other Observable Inputs (Level 2)						Significant Unobservable Inputs (Level 3)						Total
As of December 31, 2023:
Assets
Investments accounted for using measurement alternative			$	—					$	—					$	10,378					$	10,378
			$	—					$	—					$	10,378					$	10,378

The Company did not have any assets and liabilities measured at fair value on a non-recurring basis as of March 31, 2024, and the Company did not recognize any unrealized gains (upward adjustments) or unrealized losses (downward adjustments) resulting from observable price changes in orderly transactions for an identical or similar investment of the same issuer for its long-term investments accounted for using measurement alternatives during the three months ended March 31, 2024 and 2023.

Refer to Note 12 for fair value information related to the Company’s outstanding long-term borrowings as of March 31, 2024 and December 31, 2023.

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Basic and Diluted Net Income per Share of Common Stock

Basic and diluted net income per share of common stock are calculated as follows:

			Three Months Ended March 31,
			2024						2023
Numerator:
Net income			$	22,092					$	8,963
Less: Net income attributable to non-controlling interests			4,659						1,818
Net income available to common stockholders, basic			$	17,433					$	7,145
Less: Dilutive effect arising from stock-based awards by ACM Shanghai			354						93
Net income available to common stockholders, diluted			$	17,079					$	7,052
Weighted average shares outstanding, basic			61,367,184						59,736,764
Effect of dilutive securities			4,875,137						5,322,013
Weighted average shares outstanding, diluted			66,242,321						65,058,777
Net income per share of common stock:
Basic			$	0.28					$	0.12
Diluted			$	0.26					$	0.11

Basic and diluted net income per share of common stock is presented using the two-class method, which allocates undistributed earnings to common stock and any participating securities according to dividend rights and participation rights on a proportionate basis. Under the two-class method, basic net income per share of common stock is computed by dividing the sum of distributed and undistributed earnings attributable to common stockholders by the weighted average number of shares of common stock outstanding during the period. ACM Research did not have any participating securities outstanding during the three months ended March 31, 2024 and 2023.

ACM Research has been authorized to issue Class A and Class B common stock since redomesticating in Delaware in November 2016. The two classes of common stock are substantially identical in all material respects, except for voting rights. Since ACM Research did not declare any cash dividends during the three months ended March 31, 2024 or 2023, the net income per share of common stock attributable to each class is the same under the “two-class” method. As such, the two classes of common stock have been presented on a combined basis in the condensed consolidated statements of comprehensive income and in the above computation of net income per share of common stock.

Diluted net income per share of common stock reflects the potential dilution from securities, such as stock options that could share in ACM Research’s earnings. Certain potential dilutive securities were excluded from the net income per share calculation because the impact would be anti-dilutive. The number of potentially dilutive shares that were not included in the calculation of diluted net income per share in the periods presented where their inclusion would be anti-dilutive were 728,575 and 1,967,685 stock options for the three months ended March 31, 2024 and 2023, respectively.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to credit risk consist principally of cash and cash equivalents, time deposits, and accounts receivable. The Company deposits and invests its cash and cash equivalents and time deposits with financial institutions that management believes are creditworthy.

The Company is potentially subject to concentrations of credit risks in its revenue and accounts receivable. For the three months ended March 31, 2024 and 2023, two customers accounted for 55.9% and four customers accounted for 59.7% of revenue, respectively.

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As of March 31, 2024 and December 31, 2023, four customers accounted for 56.2% and four customers accounted for 59.1%, respectively, of the Company’s accounts receivables. The Company believes that the receivable balances from these largest customers do not represent a significant credit risk based on past collection experience.

Recently issued accounting pronouncements not yet adopted

In November 2023, the FASB issued ASU No. 2023-07, Improvements to Reportable Segment Disclosures. This ASU updates reportable segment disclosure requirements by requiring disclosures of significant reportable segment expenses that are regularly provided to the Chief Operating Decision Maker (“CODM”) and included within each reported measure of a segment's profit or loss. This ASU also requires disclosure of the title and position of the individual identified as the CODM and an explanation of how the CODM uses the reported measures of a segment’s profit or loss in assessing segment performance and deciding how to allocate resources. The ASU is effective for annual periods beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Adoption of the ASU should be applied retrospectively to all prior periods presented in the financial statements. Early adoption is also permitted. The Company is currently evaluating the provisions of this ASU and expect to adopt it for the year ending December 31, 2024.

In December 2023, the FASB issued ASU No. 2023-09, Improvements to Income Tax Disclosures (Topic 740). The ASU requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as additional information on income taxes paid. The ASU is effective on a prospective basis for annual periods beginning after December 15, 2024. Retrospective application is permitted. Early adoption is also permitted for annual financial statements that have not yet been issued or made available for issuance. The Company is currently evaluating the provisions of this ASU.

The Company assesses revenues based upon the nature or type of goods or services it provides and the geographic location of the customer facility. The following tables present disaggregated revenue information:

			Three Months Ended March 31,
			2024						2023
Single Wafer Cleaning, Tahoe and Semi-Critical Cleaning Equipment			$	109,470					$	36,614
ECP (front-end and packaging), Furnace and Other Technologies			25,800						26,598
Advanced Packaging (excluding ECP), Services & Spares			16,921						11,044
Total Revenue by Product Category			$	152,191					$	74,256

			Three Months Ended March 31,
			2024						2023
Mainland China			$	152,135					$	72,458
Other regions			56						1,798
			$	152,191					$	74,256

Below are the accounts receivables and contract liabilities balances as of:

			March 31, 2024						December 31, 2023
Accounts receivable			296,371						283,186
Advances from customers			182,547						181,368
Deferred revenue			4,405						3,687

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During the three months ended March 31, 2024, advances from customers increased by $1.2 million, due to an increase of payments made by customers for first tools under evaluation, offset by a decrease in customer pre-payments for tools prior to delivery.

Below are revenues recognized from amounts included in contract liabilities at the beginning of the year:

			Three Months Ended March 31,
			2024						2023
Revenue recognized from amounts included in contract liabilities at the beginning of the year			$	29,188					$	15,212

At March 31, 2024 and December 31, 2023, accounts receivable consisted of the following:

			March 31, 2024						December 31, 2023
Accounts receivable			$	302,372					$	288,016
Less: Allowance for credit losses			(6,001)						(4,830)
			$	296,371					$	283,186

The $13.2 million increase in accounts receivable for the first three months of 2024 corresponds to a $77.9 million increase in revenue for the same period.

The movement of the allowance for credit losses for the three months ended March 31, 2024 is as follows:

Allowance for credit losses, before tax, as of January 1
Provision for credit losses
Allowance for credit losses, before tax, as of March 31

March 31, 2024
$	(4,830)
(1,171)
$	(6,001)

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At March 31, 2024 and December 31, 2023, inventories consisted of the following:

			March 31, 2024						December 31, 2023
Raw materials			$	256,332					$	235,062
Work-in-process			61,871						81,438
Finished goods			262,937						228,895
Total inventory			$	581,140					$	545,395

At March 31, 2024 and December 31, 2023, the value of finished goods inventory of which were first-tools at customer physical locations for which customers were contractually obligated to take ownership upon acceptance totaled $163,484 and $123,390, respectively.

The $21,270 increase in raw materials at March 31, 2024 compared to December 31, 2023 was due to additional purchase of supplies to support a higher level of expected total shipments for the next several quarters, and to reduce the risk of supply chain delays to meet anticipated customer demand for the Company’s products.

The $34,042 increase in finished goods inventory at March 31, 2024 compared to December 31, 2023 reflects a higher value of first-tools under evaluation by existing or prospective customers, due to shipments made, net of customer acceptances during the period.

The Company’s products each require a certain degree of customization, and the substantial majority of the work-in-process inventory and finished goods inventory is built to meet a specific customer order for a repeat shipment or a first tool shipment. At the end of each period, the Company assesses the status of each item in work-in-process and finished goods inventory. The Company recognizes a loss or impairment if in management’s judgement the inventory cannot be sold or used for production, if it has been damaged or should be considered as obsolete, or if the net realizable value is lower than the cost.

At the end of each period, the Company also assesses the status of its raw materials. The Company recognizes a loss or impairment for any raw materials aged more than three years. The three-year aging is based on the Company’s assessment of technology change, its requirement to maintain stock for warranty coverage, and other factors.

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At March 31, 2024 and December 31, 2023, property, plant and equipment consisted of the following:

			March 31, 2024						December 31, 2023
Buildings and plants			$	82,933					$	83,109
Manufacturing equipment			16,702						16,556
Office equipment			5,061						4,953
Transportation equipment			402						404
Leasehold improvement			7,961						7,889
Total cost			113,059						112,911
Less: Total accumulated depreciation and amortization			(19,531)						(17,503)
Construction in progress			125,294						106,440
Total property, plant and equipment, net			$	218,822					$	201,848

Depreciation expense for the three months ended March 31, 2024 and 2023 was $2,475 and $1,714, respectively. Buildings and plants represent Lingang housing property owned by ACM Liangang at a value of RMB 249,746 ($35,189), and facilities for the new headquarters of ACM Shanghai ("Zhangjiang New Building") at a value of RMB 338,848 ($47,744), as of March 31, 2024. The Lingang housing property is pledged as security for loans from China Merchants Bank (Note 12).

A summary of land use right is as follows:

			March 31, 2024						December 31, 2023
Land use right purchase amount			$	8,977					$	8,996
Less: accumulated amortization			(672)						(629)
Land use right, net			$	8,305					$	8,367

The amortization for the three months ended March 31, 2024 and 2023 was $43 and $50, respectively.

The annual amortization of land use right is as follows:

Year ending December 31,
remainder of 2024			$	135
2025			180
2026			180
2027			180
2028			180
2029 and thereafter			7,450
Total			$	8,305

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At March 31, 2024 and December 31, 2023, other long-term assets consisted of the following:

			March 31, 2024						December 31, 2023
Prepayments for property, plant and equipment			$	7,690					$	3,380
Lease deposits			867						834
Security deposit for land use right			695						696
Others			1,219						1,140
Total other long-term assets			$	10,471					$	6,050

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At March 31, 2024 and December 31, 2023, short-term borrowings consisted of the following:

			March 31, 2024			December 31, 2023
Line of credit up to RMB 150,000 from China Everbright Bank,
1)due on August 29, 2024 with an annual interest rate of 3.00%.			2,459			2,463
Line of credit up to RMB 40,000 from Bank of China,
1)due on September 7, 2024 with an annual interest rate of 2.87%.			5,640			5,648
Line of credit up to RMB 200,000 from China Merchants Bank,
1)due on August 7, 2024 with an annual interest rate of 3.00%.			1,269			1,271
2)due on August 8, 2024 with an annual interest rate of 3.00%.			1,269			1,271
3)due on August 9, 2024 with an annual interest rate of 3.00%.			1,269			1,271
4)due on August 14, 2024 with an annual interest rate of 3.00%.			1,269			1,271
5)due on August 17, 2024 with an annual interest rate of 3.00%.			1,269			1,271
6)due on August 20, 2024 with an annual interest rate of 3.00%.			1,269			1,271
7)due on August 21, 2024 with an annual interest rate of 3.00%.			1,269			1,271
8)due on August 22, 2024 with an annual interest rate of 3.00%.			1,269			1,271
9)due on August 24, 2024 with an annual interest rate of 3.00%.			1,269			1,271
10)due on August 27, 2024 with an annual interest rate of 3.00%.			1,269			1,271
11)due on August 29, 2024 with an annual interest rate of 3.00%.			1,269			1,271
12)due on August 30, 2024 with an annual interest rate of 3.00%.			1,269			1,271
13)due on September 3, 2024 with an annual interest rate of 3.00%.			1,269			1,271
14)due on September 5, 2024 with an annual interest rate of 3.00%.			1,269			1,270
15)due on September 6, 2024 with an annual interest rate of 3.00%.			1,269			1,270
16)due on September 10, 2024 with an annual interest rate of 3.00%.			1,269			1,270
17)due on September 12, 2024 with an annual interest rate of 3.00%.			1,269			1,270
18)due on February 27, 2025 with an annual interest rate of 2.60%.			1,340			—
19)due on February 28, 2025 with an annual interest rate of 2.60%.			1,340			—
20)due on March 1, 2025 with an annual interest rate of 2.60%.			1,340			—
21)due on March 5, 2025 with an annual interest rate of 2.60%.			1,340			—
22)due on March 8, 2025 with an annual interest rate of 2.60%.			1,270			—
Line of credit up to RMB 120,000 from Bank of China,
1)due on March 20, 2025 with an annual interest rate of 2.75%.			16,921			—
Line of credit up to KRW 500,000 from Industrial Bank of Korea,
1)due on July 12, 2024 with an annual interest rate of 6.03%.			—			77
Line of credit up to KRW 2,000,000 from Industrial Bank of Korea,
1)due on December 15, 2024 with an annual interest rate of 4.27%.			1,483			1,544
Total			$	54,706		$	31,335

For the three months ended March 31, 2024 and 2023, interest expense related to short-term borrowings amounted to $213 and $490, respectively.

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At March 31, 2024 and December 31, 2023, other payables and accrued expenses consisted of the following:

			March 31, 2024			December 31, 2023
Accrued commissions			$	15,932		$	15,572
Accrued warranty			11,339			9,834
Accrued payroll			16,550			14,840
Accrued professional fees			113			696
Accrued machine testing fees			1,863			1,762
Accrued machine sales fees			4,942			6,010
Accrued Lingang construction fees			33,546			33,729
Others			22,813			20,508
Total			$	107,098		$	102,951

The Company leases space under non-cancelable operating leases for several offices and manufacturing locations. These leases do not have significant rent escalation holidays, concessions, leasehold improvement incentives, or other build-out clauses. Further, the leases do not contain contingent rent provisions.

Most leases include one or more options to renew. The Company regularly evaluates the renewal options, and when they are reasonably certain of exercise, the Company includes the renewal period in its lease term.

The components of lease expense were as follows:

			Three Months Ended March 31,
			2024			2023
Operating lease cost			$	973		$	488
Short-term lease cost			321			282
Total lease cost			$	1,294		$	770

Supplemental cash flow information related to operating leases was as follows:

			Three Months Ended March 31,
			2024			2023
Operating cash outflow from operating leases			$	973		$	488
Operating lease right-of-use assets obtained in exchange for new operating lease liabilities			$	80		$	6,592

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As of March 31, 2024, maturities of outstanding lease liabilities for all operating leases were as follows:

			December 31,
remainder of 2024			$	2,370
2025			1,800
2026			1,215
2027			1,148
2028 and thereafter			595
Total lease payments			$	7,128
Less: Interest			(630)
Present value of lease liabilities			$	6,498

The weighted average remaining lease terms and discount rates for all operating leases were as follows:

			March 31, 2024			December 31, 2023
Remaining lease term and discount rate:
Weighted average remaining lease term (years)			3.37			3.44
Weighted average discount rate			3.87		%	3.91		%

At March 31, 2024 and December 31, 2023, long-term borrowings consisted of the following:

			March 31, 2024			December 31, 2023
Loan from China Merchants Bank			$	12,919		$	13,362
Loans from Bank of China			4,759			5,013
Loan from Bank of Shanghai			14,101			14,120
Loan from China CITIC Bank			28,178			28,240
Less: Current portion			(6,549)			(6,783)
Total			$	53,408		$	53,952

The loan from China Merchants Bank is for the purpose of purchasing housing property in Lingang, Shanghai. The loan is repayable in 120 total installments with the last installment due in November 2030, with an annual interest rate of 3.95%. The loan is pledged by the property of ACM Lingang and guaranteed by ACM Shanghai.

Two loans from Bank of China are for the purpose of funding ACM Shanghai project expenditures. The loans bear interest at an annual rate of 2.6% and are repayable in 6 installments, with the last installments due in June 2024 and September 2024, respectively.

The loan from Bank of Shanghai is for the purpose of funding ACM Shanghai project expenditures. The loan bears interest at an annual rate of 2.85%, and will be fully repaid in April 2025.

The first loan from China CITIC Bank is for the purpose of funding ACM Shanghai project expenditures. The loan bears interest at an annual rate of 3.1% and is repayable in 4 installments, with the last installment due in August 2025.

The second loan from China CITIC bank is for the purpose of funding ACM's general corporate expenses and working

capital. The loan bears interest at an annual rate of 4.50% payable quarterly, and the principal amount is repayable in 4

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installments, with the last installment due in December 2025.

As of March 31, 2024 and December 31, 2023, the total carrying amount of long-term loans was $59,957 and $60,735, compared with an estimated fair value of $56,409 and $56,462, respectively. The fair value of the long-term loans is estimated by discounting cash flows using interest rates currently available for debts with similar terms and maturities (Level 2 fair value measurement). Refer to Note 2 for an explanation of the fair value hierarchy structure.

Scheduled principal payments for the outstanding long-term loan, including the current portion, as of March 31, 2024 are as follows:

Year ending December 31
remainder of 2024			$	6,120
2025			43,993
2026			1,851
2027			1,925
2028			2,003
Thereafter			4,065
			$	59,957

Other long-term liabilities represent government subsidies received from mainland China governmental authorities for development and commercialization of certain technology but not yet recognized. At March 31, 2024 and December 31, 2023, other long-term liabilities consisted of the following unearned government subsidies:

			March 31, 2024			December 31, 2023
Subsidies to Stress Free Polishing project, commenced in 2008 and 2017			$	189		$	475
Subsidies to other cleaning tools, commenced in 2020			647			632
Subsidies to SW Lingang R&D development in 2021			3,454			3,467
Other			1,179			1,299
Total			$	5,469		$	5,873

On January 12, 2024, ACM Shanghai entered into an investment agreement with Company C to invest RMB 12,500 ($1,760), which represented 0.3% of the Company C's total equity interest. Since there is no readily determinable fair value, the Company measures the investments at measurement alternative.

On January 19, 2024, ACM Shanghai entered into a limited partnership agreement with Company D to invest RMB 30,000 ($4,230), which represented 16.7% of the partnership's total equity interest. The investment in the limited partnership with Company D is accounted for under the equity method in accordance with ASC323-30-S99-1.

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Equity investee:

Initial investment dates

Investment entity

Percent ownership by ACM and subsidiaries

Investment purchase price

Ninebell Co., Ltd. ("Ninebell")

September 2017

ACM

20.0%

$

1,200

Shengyi Semiconductor Technology Co., Ltd. ("Shengyi")

June 2019

ACM Shanghai

14.0%

$

109

Hefei Shixi Chanheng Integrated Circuit Industry Venture Capital FundPartnership (LP) (“Hefei Shixi”)

September 2019

ACM Shanghai

10.0%

RMB 30,000 ($4,200)

Wooil Flucon Co. ("Wooil")

August 2022

ACM Singapore

20.0%

$

1,000

Company D

February 2024

ACM Shanghai

16.7%

RMB 30,000 ($4,230)

Investments accounted for using measurement alternative:

Waferworks (Shanghai) Co., Ltd. (“Waferworks”)

October 2021

ACM Shanghai

0.3%

$

1,568

Company A

September 2023

ACM Shanghai

4.4%

RMB 30,000 ($4,200)

Shengyi

September 2023

ACM Shanghai

1.0%

RMB 6,100 ($860)

Company B

November 2023

ACM Shanghai

1.4%

RMB 6,600 ($930)

Company C

February 2024

ACM Shanghai

5.0%

RMB 12,500 ($1,760)

Equity investee:			March 31, 2024			December 31, 2023
Ninebell			$	5,481		$	5,632
Wooil			989			1,003
Shengyi			1,999			1,693
Hefei Shixi			7,888			9,174
Company D			4,227			—
Subtotal			20,584			17,502
Investments accounted for using measurement alternative:
Waferworks			—			1,412
Shengyi			856			857
Company A			4,227			4,236
Company B			930			932
Company C			1,761			—
Other			2,935			2,941
Total			31,293			27,880

For the three months ended March 31, 2024 and 2023, the Company’s share of equity investees’ net loss was $520 and $32, respectively, which amounts were included in loss from equity method investments in the accompanying condensed consolidated statements of comprehensive income. For the three months ended March 31, 2024 and 2023, the Company received $600 and $0 dividends from equity investee.

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Pursuant to an Agreement entered into on September 19, 2022 (the ‘‘Agreement’’), ACM Shanghai became a limited partner of the Nuode Asset Fund Pujiang No. 783 Single Asset Management Plan (‘‘Nuode Asset Fund’’), a Chinese limited partnership formed by Nuode Asset Management Co., Ltd, a financial services firm based in Shanghai, China. Nuode Asset Fund was formed to establish a special fund with the purpose to participate in certain technology related investments in mainland China. Subsequent to the future purchase, any investment will be held by Nuode Asset Fund and restricted for a minimum period of nine months. The limited partners of the Nuode Asset Fund contributed a total RMB 160 million ($22,160) to the fund, of which ACM Shanghai contributed RMB 30 million ($4,196), or 18.75% of the contribution on September 27, 2022.

In December 2022, the Nuode Asset Fund purchased shares in the secondary stock offering of a publicly traded mainland China-stock listing. The number of shares owned by Nuode Asset Fund was apportioned to all of the limited partners in proportion to their respective capital contributions which is 18.75% in the case of ACM Shanghai. The investments were fully disposed in the three months ended March 31, 2024 and the Company has not received the proceeds as of March 31, 2024 with a receivable of RMB 22,478 ($3,167) was recorded.

Pursuant to a Share Purchase Agreement dated June 2023, ACM Shanghai acquired shares of Huahong Semiconductor Limited (“Huahong”) in July 2023 with amount of RMB 100 million ($13,930). The shares held by ACM Shanghai are restricted for sale for a minimum period of twelve months. Huahong completed its STAR IPO in August 2023.

Pursuant to a Share Purchase Agreement dated August 2023, ACM Shanghai acquired shares of Zhongjuxin Limited Company (“Zhongjuxin”) in September 2023 with amount of RMB 30 million ($4,179). The shares held by ACM Shanghai are restricted for sale for a minimum period of twelve months. Zhongjuxin completed its STAR IPO in September 2023.

Pursuant to a Share Purchase Agreement dated January 2024, ACM Shanghai acquired shares of Shanghai Syncrystalline Silicon Materials Co., Ltd. (“Syncrystalline”) in February 2024 with amount of RMB 10,000 ($1,409). The shares held by ACM Shanghai are restricted for sale for a minimum period of twelve months. Syncrystalline completed its STAR IPO in February 2024. As of March 31, 2024, the Company's total investment costs in Syncrystalline were RMB 20,000($2,818), including RMB 10,000 ($1,409) invested by ACM Shanghai in 2021 and RMB 10,000 ($1,409) invested by ACM Shanghai in February 2024.

At March 31, 2024 and December 31, 2023, the components of short-term investments were as follows:

			March 31, 2024			December 31, 2023
Short-term investments listed in Shanghai Stock Exchange
Cost			$	21,135		$	20,155
Market value			18,648			21,312

For the three months ended March 31, 2024 and 2023, the net gains (losses) recognized on equity securities were as follows:

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			Three Months Ended March 31,
			2024			2023
Unrealized losses recognized during the reporting period on equity securities still held at March 31			$	(2,595)		$	(654)
Net gains recognized during the period on equity securities sold during the period			$	273		$	3,994
Total net gains (losses) recognized at March 31 on equity securities			$	(2,322)		$	3,340

For the three months ended March 31, 2024, the Company recognized a receivable of RMB 22,478 ($3,167) from the sales of short-term investments, including a realized gain of $273.

For the three months ended March 31, 2023, the Company received $11,072 in proceeds from the sale of short-term investments, including a realized gain of $3,994.

Ninebell

Ninebell is an equity investee of ACM (Note 14) and is the Company’s principal supplier of robotic delivery system subassemblies used in our single-wafer cleaning equipment. The Company purchases equipment from Ninebell for production in the ordinary course of business. The Company pays for a portion of the equipment in advance and is obligated for the remaining amounts upon receipt of the product.

Shengyi

Shengyi is an equity investee of ACM Shanghai (Note 14) and is one of the Company’s component suppliers in mainland China. The Company purchases components from Shengyi for production in the ordinary course of business. The Company incurs a service fee related to installation and hook-up fees which is recorded within cost of revenue on the Company’s condensed consolidated statements of comprehensive income. The Company pays for a portion of the raw materials in advance and is obligated for the remaining amounts upon receipt of the product.

All related party outstanding balances are short-term in nature and are expected to be settled in cash.

The following tables reflect related party transactions in our condensed consolidated financial statements:

Advances to related party			March 31, 2024			December 31, 2023
Ninebell			$	1,338		$	2,432

Accounts payable			March 31, 2024			December 31, 2023
Ninebell			$	12,571		$	7,624
Shengyi			3,672			3,783
Total			$	16,243		$	11,407

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			Three Months Ended March 31,
Purchase of materials			2024			2023
Ninebell			$	14,152		$	16,397
Shengyi			992			1,973
Total			$	15,144		$	18,370

			Three Months Ended March 31,
Service fee charged by			2024						2023
Shengyi			$	73					$	278

ACM is authorized to issue 150,000,000 shares of Class A common stock and 5,307,816 shares of Class B common stock, each with a par value of $0.0001. Each share of Class A common stock is entitled to one vote, and each share of Class B common stock is entitled to twenty votes and is convertible at any time into one share of Class A common stock. Shares of Class A common stock and Class B common stock are treated equally, identically and ratably with respect to any dividends declared by the Board of Directors of ACM unless such Board of Directors declares different dividends to the Class A common stock and Class B common stock, which is subject to approval from a majority of common stockholders.

During the three months ended March 31, 2024, ACM issued 950,605 shares of Class A common stock upon option exercises by employees and non-employees.

During the three months ended March 31, 2023, ACM issued 163,069 shares of Class A common stock upon option exercises by employees and non-employees.

At March 31, 2024 and December 31, 2023, the number of shares of Class A common stock issued and outstanding was 56,986,777 and 56,036,172, respectively.

At March 31, 2024 and December 31, 2023, the number of shares of Class B common stock issued and outstanding was 5,021,811 and 5,021,811, respectively.

ACM’s stock-based compensation consists of employee and non-employee awards issued under its 1998 Stock Option Plan and its 2016 Omnibus Incentive Plan. The vesting condition may consist of a service period condition determined by the Board of Directors for a grant or certain performance conditions determined by the Board of Directors for a grant. The fair value of the stock options granted with a service period based condition and/or performance condition is estimated at the date of grant using the Black-Scholes option pricing model. The fair value of the stock options granted with a market based condition is estimated at the date of grant using the Monte Carlo simulation model.

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Employee Awards

The following table summarizes the Company’s employee share option activities during the three months ended March 31, 2024:

			Number of  Option Shares			Weighted  Average Grant Date Fair Value			Weighted Average Exercise Price			Weighted Average Remaining Contractual Term
Outstanding at December 31, 2023			9,998,637			$	5.15		$	9.59		6.17 years
Granted			3,000			23.95			31.92
Exercised			(851,954)			2.7			5.74
Forfeited/cancelled			(24,330)			11.14			23.08
Outstanding at March 31, 2024			9,125,353			$	5.37		$	9.79		6.07 years
Vested and exercisable at March 31, 2024			5,278,784

As of March 31, 2024 and December 31, 2023, $24,670 and $27,152, respectively, of total unrecognized employee stock-based compensation expense, net of estimated forfeitures, related to employee stock-based awards for ACM were expected to be recognized over a weighted-average period of 3.8 years and 4.0 years, respectively. Total recognized compensation cost may be adjusted for future changes in estimated forfeitures.

The aggregate intrinsic value of options exercised in the three months ended March 31, 2024 was $21,865. The aggregate intrinsic value of options outstanding and exercisable as of March 31, 2024 were $178,674 and $117,476, respectively.

The fair value of options granted to employees is estimated on the grant date using the Black-Scholes valuation with following assumptions:

			Three Months Ended March 31, 2024
Fair value of common share(1)			31.92
Expected term in years(2)			6.25
Volatility(3)			85.48%
Risk-free interest rate(4)			4.23%
Expected dividend (5)			—%

(1)Fair value of Class A common stock value was closing market price of the Class A common stock on the grant date.

(2)Expected term of share options is based on the average of the vesting period and the contractual term for each grant.

(3)Volatility is calculated based on the historical volatility of ACM in the period equal to the expected term of each grant.

(4)Risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected term of the share options in effect at the time of grant.

(5)Expected dividend is assumed to be 0% as ACM has no history or expectation of paying a dividend on its common stock.

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Non-employee Awards

The following table summarizes the Company’s non-employee share option activities during the three months ended March 31, 2024:

			Number of Option Shares			Weighted Average Grant Date Fair Value			Weighted Average Exercise Price			Weighted Average Remaining Contractual Term
Outstanding at December 31, 2023			1,170,795			$	0.42		$	1.31		2.66 years
Exercised			(98,651)			0.22			0.50
Forfeited/cancelled			(1,903)			0.22			0.50
Outstanding at March 31, 2024			1,070,241			$	0.44		$	1.39		2.51 years
Vested and exercisable at March 31, 2024			1,070,241

As of March 31, 2024 and December 31, 2023, $0 and $9, respectively, of total unrecognized non-employee stock-based compensation expense, net of estimated forfeitures, related to stock-based awards were expected to be recognized over a weighted-average period of 0 years and 0.2 years, respectively. Total recognized compensation cost may be adjusted for future changes in estimated forfeitures.

The aggregate intrinsic value of options exercised in the three months ended March 31, 2024 was $2,756. The aggregate intrinsic value of options outstanding and exercisable as of March 31, 2024 was $29,702.

ACM Shanghai 2019 Option Grants

In January 2020, ACM Shanghai adopted a 2019 Stock Option Incentive Plan (the “2019 Subsidiary Stock Option Plan”) that provides for, among other incentives, the granting to officers, directors, and employees of options to purchase shares of ACM Shanghai’s common stock.

The following table summarizes the stock option activities of the ACM Shanghai 2019 Subsidiary Stock Option Plan during the three months ended March 31, 2024:

			Number of Option Shares in ACM Shanghai			Weighted Average Grant Date Fair Value			Weighted Average Exercise Price			Weighted Average  Remaining Contractual Term
Outstanding at December 31, 2023			3,134,883			$	0.24		$	1.85		0.85 years
Forfeited/cancelled			(92,308)			$	0.24		$	1.85
Outstanding at March 31, 2024			3,042,575			$	0.24		$	1.85		0.65 years
Vested and exercisable at March 31, 2024			3,042,575

The aggregate intrinsic value of options exercised in the three months ended March 31, 2024 was $0. The aggregate intrinsic value of options outstanding and exercisable as of March 31, 2024 was $31,616.

ACM Shanghai 2023 Option Grants

In June 2023, ACM Shanghai adopted a 2023 Stock Option Incentive Plan (the "2023 Subsidiary Stock Option Plan”) that provides for, among other incentives, the granting to officers, directors, and employees of options to purchase shares of ACM Shanghai’s common stock. The vesting conditions consist of service periods conditions and performance conditions

---

related to certain sales and research and development progress targets determined by the Board of Directors of ACM Shanghai.

The following table summarizes the ACM Shanghai 2023 Subsidiary Stock Option Plan’s stock option activities during the three months ended March 31, 2024:

			Number of Option Shares in ACM Shanghai						Weighted Average Grant Date Fair Value						Weighted Average Exercise Price						Weighted Average  Remaining Contractual Term
Outstanding at December 31, 2023			10,575,500						$	9.49					$	7.06					3.09 years
Forfeited/cancelled			(84,000)						$	9.49					$	7.06
Outstanding at March 31, 2024			10,491,500						$	9.12					$	7.01					2.84 years
Vested and exercisable at March 31, 2024			-

During the three months ended March 31, 2024, ACM Shanghai did not grant any options from the 2023 Subsidiary Stock Option Plan. As of March 31, 2024 and December 31, 2023, $65,682 and $79,882, respectively, of total unrecognized non-employee stock-based compensation expense, net of estimated forfeitures, related to ACM Shanghai stock-based awards were expected to be recognized over a weighted-average period of 1.8 years and 2.1 years, respectively. Total recognized compensation cost may be adjusted for future changes in estimated forfeitures.

The aggregate intrinsic value of options exercised in the three months ended March 31, 2024 was $0. The aggregate intrinsic value of options outstanding and exercisable as of March 31, 2024 were $54,686 and $0, respectively.

The following table summarizes the components of stock-based compensation expense included in the condensed consolidated statements of comprehensive income:

			Three Months Ended March 31,
			2024			2023
Stock-Based Compensation Expense:
Cost of revenue			$	781		$	125
Sales and marketing expense			3,027			431
Research and development expense			4,503			701
General and administrative expense			6,258			811
			$	14,569		$	2,068

			Three Months Ended March 31,
			2024			2023
Stock-based compensation expense by type:
Employee stock purchase plan			$	2,353		$	2,018
Non-employee stock purchase plan			9			11
2019 and 2023 Subsidiary option grants			12,207			39
			$	14,569		$	2,068

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Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carry-forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period during which such rates are enacted.

The Company considers all available evidence to determine whether it is more likely than not that some portion or all of the deferred tax assets will be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become realizable. Management considers the scheduled reversal of deferred tax liabilities (including the impact of available carryback and carry-forward periods) and projected taxable income in assessing the realizability of deferred tax assets. In making such judgments, significant weight is given to evidence that can be objectively verified.

As of each reporting date, management considers new evidence, both positive and negative, that could affect its view of the future realization of deferred tax assets. Prior to September 30, 2019, the Company had recorded a valuation allowance for the full amount of net deferred tax assets in the United States, as the realization of deferred tax assets was uncertain. Since September 30, 2019, the Company has not maintained a valuation allowance except for a partial valuation allowance on certain U.S. and foreign deferred tax assets. In order to recognize the remaining U.S. deferred tax assets that continue to be subject to a valuation allowance, the Company will need to generate sufficient U.S. taxable income in future periods before the expiration of the deferred tax assets governed by the tax code.

ACM Shanghai has shown a three-year historical cumulative profit and has projections of future income. As a result, the Company does not maintain a valuation allowance.

The Company accounts for uncertain tax positions in accordance with the authoritative guidance on income taxes under which the Company may only recognize or continue to recognize tax positions that meet a more likely than not threshold. The Company recognizes accrued interest and penalties related to unrecognized tax benefits as a component of the provision for income taxes.

The Company’s effective tax rate differs from statutory rates of 21% for U.S. federal income tax purposes and 15% to 25% for Chinese income tax purposes due to the effects of the valuation allowance and certain permanent differences from book-tax differences, including stock based compensation, deemed dividend income under Subchapter F of the U.S. Internal Revenue Code of 1986, as amended (Subpart F), and global intangible low-taxed income (GILTI) inclusions, and R&D super deduction. As a result, the Company recorded income tax expense of $4,369 and $2,879 during the three months ended March 31, 2024 and 2023, respectively. The decrease in the Company's effective income tax rate for the three months ended March 31, 2024 compared to the same period of the prior year was primarily due to an increased benefit from certain permanent deductions in a foreign jurisdiction.

Under the change in Section 174 made by the Tax Cuts and Jobs Act of 2017 which became effective on January 1, 2022, the Company is required to capitalize, and subsequently amortize R&D expenses over fifteen years for research activities conducted outside of the U.S. The capitalization of overseas R&D expenses results in a significant increase in the Company’s global intangible low-taxed income inclusion.

The Company had total unrecognized tax benefits of $13,026 as of both March 31, 2024 and December 31, 2023. If recognized, the net impact to effective rate, after indirect offset, would be $12,943. The Company did not expect any reversal of unrecognized tax benefits in the next 12 months. The Company will recognize interest and penalties, when they occur, related to uncertain tax provisions as a component of tax expense. For the three months ended March 31, 2024 and 2023, $338 and $284 of interest and penalties was recognized, respectively.

The Company is subject to taxation in the United States, state, and foreign jurisdictions. All tax returns will remain open for examination by the federal and state authorities for three and four years, respectively, from the date of utilization of any

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net operating loss or credits. Certain tax years are subject to foreign income tax examinations by tax authorities until the statute of limitations expire.

The Company’s four principal mainland China subsidiaries, ACM Shanghai, ACM Wuxi, ACM Beijing and ACM Lingang, are liable for mainland China corporate income taxes at the rates of 15%, 25%, 25% and 15%, respectively. Pursuant to the Corporate Income Tax Law of mainland China, ACM’s mainland China subsidiaries generally would be liable for mainland China corporate income taxes as a rate of 25%. According to Guoshuihan 2009 No. 203, an entity certified as an “advanced and new technology enterprise” is entitled to a preferential income tax rate of 15%. ACM Shanghai was certified as an “advanced and new technology enterprise” in 2012 and again in 2016, 2018, and 2021, with an effective period of three years and is expected to be re-certified for future years in 2024. In 2022, ACM Shanghai was certified as an eligible integrated circuit production enterprise and was entitled to a preferential income tax rate of 12.5% from January 1, 2020 to December 31, 2022. Certain entities which meet requirements according to the Policy of the Lingang New area in China (Shanghai) Pilot Free Trade Zone are entitled to a preferential income tax rate of 15%. ACM Lingang was certified for this in 2021, and this preferential income tax rate is valid from January 1, 2020 until December 31, 2024.

Income tax expense was as follows:

			Three Months Ended March 31,
			2024			2023
Total income tax expense			$	(4,369)		$	(2,879)

The Company leases offices under non-cancelable operating lease agreements. See Note 11 for future minimum lease payments under non-cancelable operating lease agreements with initial terms of one year or more.

As of March 31, 2024, the Company had $24,285 of open capital commitments to construction contracts and had additional $1,409 of capital investment commitments. As of December 31, 2023, the Company had $30,936 of open commitments to construction contracts and had additional $7,413 of capital investment commitments.

Covenants in ACM Lingang’s Grant Contract for State-owned Construction Land Use Right in Shanghai City (Category of R&D Headquarters and Industrial Projects) with the China (Shanghai) Pilot Free Trade Zone Lingang Special Area Administration require, among other things, that ACM Lingang pay liquidated damages in the event that (a) it does not make a total investment (including the costs of construction, fixtures, equipment and grant fees) of at least RMB 450.0 million ($62,600) or (b) within six years after the land use right is obtained, the Company does not (i) generate a minimum specified amount of annual sales of products manufactured on the granted land or (ii) pay to mainland China at least RMB 157.6 million ($22,000) in annual total taxes (including value-added taxes, corporate income tax, personal income taxes, urban maintenance and construction taxes, education surcharges, stamp taxes, and vehicle and shipping taxes) as a result of operations in connection with the granted land.

As of March 31, 2024 and December 31, 2023, the Company had paid in total $132,014 and $116,932, respectively for its Lingang-related investments. The Construction Completion Milestone was required to be met by January 9, 2024 but was not achieved. However, ACM Lingang believes it will receive the refund without penalty based on its explanation to the respective regulatory authorities of logistics-related delays, and expects that it will meet the milestone before July 9, 2024. The Company cannot guarantee that ACM Lingang will achieve the missed milestone in 2024, or even if it does achieve the milestone in 2024, that it will be refunded some or all of the 20% portion of the performance deposit of RMB 2.5 million ($0.4 million).

In the normal course of business, the Company is subject to contingencies, including legal proceedings and environmental claims arising out of the normal course of businesses that relate to a wide range of matters, including among others, contracts breach liability. The Company records accruals for such contingencies based upon the assessment of the probability of occurrence and, where determinable, an estimate of the liability. Management may consider many factors in

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making these assessments including past history, scientific evidence and the specifics of each matter. Some of these contingencies involve claims that are subject to substantial uncertainties and un-estimable damages.

The Company’s management has evaluated all such proceedings and claims that existed as of March 31, 2024 and December 31, 2023. In the opinion of management, no provision for liability nor disclosure was required as of March 31, 2024 related to any claim against the Company because: (a) there is not a reasonable possibility that a loss exceeding amounts already recognized (if any) may be incurred with respect to such claim; (b) a reasonably possible loss or range of loss cannot be estimated; or (c) such estimate is immaterial.

As of March 31, 2024, the Company had no outstanding legal proceedings.

The Company identifies operating segments according to how the business activities are managed and evaluated. The Company’s chief operating decision maker (“CODM”) has been identified as ACM’s Chief Executive Officer. The Company's operating segments include ACM Research and ACM Shanghai. As the Company is engaged in the developing, manufacture and sale of capital equipment to global semiconductor manufacturers, and each of the operating segments share similar economic and other qualitative characteristics, the results of the Company’s operating segments are aggregated into one reportable segment.

For geographical reporting, revenue by geographic location is determined by the location of customers’ facilities to which products were shipped. Long-lived assets consist primarily of property, plant and equipment, land use right, and right-of-use assets and are attributed to the geographic location in which they are located.

Long-lived assets by geographic region as of the periods ended were as follows:

			March 31, 2024			December 31, 2023
Long-lived assets by geography:
Mainland China			$	231,208		$	209,725
Korea			11,630			12,190
United States			1,259			1,276
Total			$	244,097		$	223,191

In accordance with mainland China’s Foreign Enterprise Law, ACM Shanghai, ACM Lingang, and ACM Wuxi are required to make appropriation to reserve funds, comprising the statutory surplus reserve and discretionary surplus reserve, based on after-tax net income in accordance with generally accepted accounting principles of mainland China (“mainland China GAAP”).

Appropriations to the statutory surplus reserve are required to be at least 10% of the after-tax net income determined in accordance with mainland China GAAP until the reserve is equal to 50% of the entities’ registered capital. The amount is calculated annually at the end of each calendar year. The balances of statutory reserve funds was $30,060 as of both March 31, 2024 and December 31, 2023, and is presented as statutory surplus reserve on the Company’s condensed consolidated balance sheets.

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On March 7, 2024, Jian Wang, Chief Executive Officer and President of ACM Shanghai, adopted a Rule 10b5-1 trading arrangement (the “Wang Plan”) that is intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act. The Wang Plan allows for the contemporaneous exercise of options and sale of up to 120,000 shares of Class A common stock, at specific market prices, commencing on June 6, 2024, and continuing until (i) all such options are exercised and the underlying shares are sold, (ii) December 31, 2024, or (iii) such date that the Wang Plan is otherwise terminated according to its terms, whichever comes first.

On March 7, 2024, Mark McKechnie, Chief Financial Officer of ACM Research, adopted a Rule 10b5-1 trading arrangement (the “McKechnie Plan”) that is intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act. The McKechnie Plan allows for the contemporaneous exercise of options and sale of up to 81,516 shares of Class A common stock, at specific market prices, commencing on June 6, 2024, and continuing until (i) all such options are exercised and the underlying shares are sold, (ii) December 31, 2025, or (iii) such date that the McKechnie Plan is otherwise terminated according to its terms, whichever comes first.

On March 14, 2024, Lisa Feng, Chief Financial Officer of ACM Shanghai, adopted a Rule 10b5-1 trading arrangement (the “Feng Plan”) that is intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act. The Feng Plan allows for the contemporaneous exercise of options and sale of up to 30,000 shares of Class A common stock, at specific market prices, commencing on June 13, 2024, and continuing until (i) all such options are exercised and the underlying shares are sold, (ii) June 4, 2025, or (iii) such date that the Feng Plan is otherwise terminated according to its terms, whichever comes first.

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v3.24.1.u1

Cover Page - shares	3 Months Ended
	Mar. 31, 2024	May 03, 2024
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-38273
Entity Registrant Name	ACM Research, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-3290283
Entity Address, Address Line One	42307 Osgood Road, Suite I
Entity Address, City or Town	Fremont
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94539
City Area Code	510
Local Phone Number	445-3700
Title of 12(b) Security	Class A Common Stock, $0.0001 par value
Trading Symbol	ACMR
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0001680062
Document Fiscal Year Focus	2024
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q1
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		56,986,777
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		5,021,811

v3.24.1.u1

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 211,305	$ 182,090
Restricted cash	808	1,083
Short-term time deposits (note 2)	48,364	80,524
Short-term investments (note 15)	18,648	21,312
Accounts receivable, net (note 4)	296,371	283,186
Inventories, net (note 5)		545,395
Prepaid expenses	20,066	20,023
Total current assets	1,229,356	1,176,110
Property, plant and equipment, net (note 6)	218,822	201,848
Land use right, net (note 7)	8,305	8,367
Operating lease right-of-use assets, net (note 11)	6,498	7,026
Intangible assets, net	2,803	2,538
Long-term time deposits (note 2)	27,841	40,818
Deferred tax assets (note 19)	21,360	20,271
Long-term investments (note 14)	31,293	27,880
Other long-term assets (note 8)	10,471	6,050
Total assets	1,556,749	1,490,908
Current liabilities:
Short-term borrowings (note 9)	54,706	31,335
Current portion of long-term borrowings (note 12)	6,549	6,783
Advances from customers (note 3)	182,547	181,368
Deferred revenue (note 3)	4,405	3,687
Income taxes payable (note 19)	11,403	6,401
FIN-48 payable (note 19)	12,131	12,149
Other payables and accrued expenses (note 10)	107,098	102,951
Current portion of operating lease liabilities (note 11)	2,668	2,764
Total current liabilities	533,249	500,659
Long-term borrowings (note 12)	53,408	53,952
Long-term operating lease liabilities (note 11)	3,830	4,262
Other long-term liabilities (note 13)	5,469	5,873
Total liabilities	595,956	564,746
Commitments and contingencies (note 21)
Equity:
Additional paid-in capital	646,800	629,845
Retained earnings	174,260	156,827
Statutory surplus reserve (note 22)	30,060	30,060
Accumulated other comprehensive loss	(54,925)	(49,349)
Total ACM Research, Inc. stockholders’ equity	796,202	767,390
Non-controlling interests	164,591	158,772
Total equity	960,793	926,162
Total liabilities and equity	1,556,749	1,490,908
Related Party
Current assets:
Other receivables	1,338	2,432
Inventories, net (note 5)	581,140
Current liabilities:
Accounts payable	16,243	11,407
Nonrelated Party
Current assets:
Other receivables	51,316	40,065
Current liabilities:
Accounts payable	135,499	141,814
Class A Common Stock
Equity:
Common stock	6	6
Class B Common Stock
Equity:
Common stock	$ 1	$ 1

v3.24.1.u1

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Revenue (note 3)	$ 152,191	$ 74,256
Cost of revenue, including cost of revenue from related parties of $15.1 million and $18.4 million for the three months ended March 31, 2024 and 2023, respectively (note 16)	73,070	34,270
Gross profit	79,121	39,986
Operating expenses:
Sales and marketing	14,173	9,337
Research and development	23,918	14,029
General and administrative	15,798	7,758
Total operating expenses	53,889	31,124
Income from operations	25,232	8,862
Interest income	1,774	1,785
Interest expense	(783)	(695)
Realized gain from sale of short-term investments (note 15)	273	3,994
Unrealized loss on short-term investments (note 15)	(2,595)	(654)
Other income (expense), net	3,080	(1,418)
Loss from equity method investments (note 14)	(520)	(32)
Income before income taxes	26,461	11,842
Income tax expense (note 19)	(4,369)	(2,879)
Net income	22,092	8,963
Less: Net income attributable to non-controlling interests	4,659	1,818
Net income attributable to ACM Research, Inc.	17,433	7,145
Net income available to common stockholders, diluted	17,079	7,052
Comprehensive income:
Net income	22,092	8,963
Foreign currency translation adjustment, net of tax	(6,829)	9,423
Comprehensive income	15,263	18,386
Less: Comprehensive income attributable to non-controlling interests	3,406	3,462
Comprehensive income attributable to ACM Research, Inc.	$ 11,857	$ 14,924
Net income attributable to ACM Research, Inc. per share of common stock (note 2):
Basic (in dollars per share)	$ 0.28	$ 0.12
Diluted (in dollars per share)	$ 0.26	$ 0.11
Weighted average shares of common stock outstanding used in computing per share amounts (note 2):
Basic (in shares)	61,367,184	59,736,764
Diluted (in shares)	66,242,321	65,058,777

v3.24.1.u1

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cost of revenue, related party	$ 73,070	$ 34,270
Related Party
Cost of revenue, related party	$ 15,100	$ 18,400

v3.24.1.u1

Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock Class A	Common Stock Class B	Common Stock Common Stock Class A	Common Stock Common Stock Class B	Additional Paid- in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Statutory Surplus Reserve	Accumulated Other Comprehensive Income (Loss)	Non-controlling Interests	Non-controlling Interests Cumulative Effect, Period of Adoption, Adjustment
Beginning balance (in shares) at Dec. 31, 2022					54,655,286	5,021,811
Beginning balance at Dec. 31, 2022	$ 812,171	$ (1,769)			$ 5	$ 1	$ 604,089	$ 94,426	$ (1,769)	$ 16,881	$ (40,546)	$ 137,315	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	8,963							7,145				1,818
Foreign currency translation adjustment	9,423										7,778	1,645
Exercise of stock options (in shares)			163,069		163,069
Exercise of stock options	241						241
Stock-based compensation	2,068						2,068
Ending balance (in shares) at Mar. 31, 2023					54,818,355	5,021,811
Ending balance at Mar. 31, 2023	831,097				$ 5	$ 1	606,398	99,802		16,881	(32,768)	140,778
Beginning balance (in shares) at Dec. 31, 2023			56,036,172	5,021,811	56,036,172	5,021,811
Beginning balance at Dec. 31, 2023	926,162				$ 6	$ 1	629,845	156,827		30,060	(49,349)	158,772
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	22,092							17,433				4,659
Foreign currency translation adjustment	(6,829)										(5,576)	(1,253)
Exercise of stock options (in shares)					950,605
Exercise of stock options	4,799				$ 0		4,799					0
Stock-based compensation	14,569						12,156					2,413
Ending balance (in shares) at Mar. 31, 2024			56,986,777	5,021,811	56,986,777	5,021,811
Ending balance at Mar. 31, 2024	$ 960,793				$ 6	$ 1	$ 646,800	$ 174,260		$ 30,060	$ (54,925)	$ 164,591

v3.24.1.u1

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net income	$ 22,092	$ 8,963
Adjustments to reconcile net income from operations to net cash used in operating activities
Non-cash operating lease cost	973	488
Depreciation and amortization	2,518	1,714
Realized gain on short-term investments	(273)	(3,994)
Loss from equity method investments	520	32
Unrealized loss on short-term investments	2,595	654
Inventory provision	1,025	306
Provision for credit losses	1,171	298
Deferred income taxes	(1,129)	(6,294)
Stock-based compensation	14,569	2,068
Net changes in operating assets and liabilities:
Accounts receivable	(15,286)	(2,452)
Other receivables	(11,580)	(5,423)
Inventories	(38,574)	(80,248)
Advances to related party (note 16)	1,094	1,016
Prepaid expenses	(141)	(3,362)
Related party accounts payable (note 16)	4,836	3,886
Accounts payable	(5,553)	13,250
Advances from customers	2,182	25,857
Deferred revenue	4,892	3,407
Income taxes payable	5,009	6,683
FIN-48 payable	(19)	88
Other payables and accrued expenses	807	1,327
Operating lease liabilities	(973)	(488)
Other long-term liabilities	(404)	1,730
Net cash used in operating activities	(9,649)	(30,494)
Cash flows from investing activities:
Purchase of property and equipment	(25,419)	(14,895)
Purchase of intangible assets	(668)	(155)
Purchase of short-term investments (note 15)	(1,409)	(728)
Purchase of time deposits	(45,270)	(14,120)
Proceeds from maturity of time deposits	90,445	67,955
Proceeds from sale of short-term investments (note 15)	0	11,072
Purchase of long-term investments (note 14)	(5,988)	0
Dividends from unconsolidated affiliates	600	0
Net cash provided by investing activities	12,291	49,129
Cash flows from financing activities:
Proceeds from short-term borrowings	23,530	0
Repayments of short-term borrowings	(287)	0
Repayments of long-term borrowings	(1,193)	(1,696)
Proceeds from exercise of stock options	4,799	241
Net cash provided by (used in) financing activities	26,849	(1,455)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(551)	(4,784)
Net increase in cash, cash equivalents and restricted cash	28,940	12,396
Cash, cash equivalents and restricted cash at beginning of period	183,173	248,451
Cash, cash equivalents and restricted cash at end of period	212,113	260,847
Supplemental disclosure of cash flow information:
Interest paid, net of capitalized interest	783	695
Cash paid for income taxes	0	2,874
Reconciliation of cash, cash equivalents and restricted cash in consolidated statements of cash flows:
Cash and cash equivalents	211,305	260,387
Restricted cash	808	460
Cash, cash equivalents and restricted cash	212,113	260,847
Other Noncash Investing and Financing Items [Abstract]
Cashless exercise of stock options	140	47
Proceeds from sale of short-term investments included in other receivables	3,167	0
Transfer from inventory to property, plant and equipment	0	4,557
Transfer of prepayment for property to property, plant, and equipment	$ 5,320	$ 161

v3.24.1.u1

DESCRIPTION OF BUSINESS	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
DESCRIPTION OF BUSINESS	DESCRIPTION OF BUSINESS ACM Research, Inc. (“ACM” or “ACM Research”) and its subsidiaries (collectively with ACM, the “Company”) develop, manufacture and sell capital equipment to the global semiconductor industry. ACM was incorporated in California in 1998, and it initially focused on developing tools for manufacturing process steps involving the integration of ultra low-K materials and copper. The Company’s early efforts focused on stress-free copper-polishing technology, and it sold tools based on that technology in the early 2000s. In 2006, the Company established its operational center in Shanghai in the People’s Republic of China (“mainland China”), where it operates through ACM’s subsidiary, ACM Research (Shanghai), Inc. (“ACM Shanghai”). ACM Shanghai was formed to help establish and build relationships with integrated circuit manufacturers in mainland China, and the Company initially financed its Shanghai operations in part through sales of non-controlling equity interests in ACM Shanghai. In 2007, the Company began to focus its development efforts on single-wafer wet-cleaning solutions for the front-end chip fabrication process. The Company introduced its SAPS megasonic technology, which can be applied in wet wafer cleaning at numerous steps during the chip fabrication process, in 2009. It introduced its TEBO technology, which can be applied at numerous steps during the fabrication of small node two-dimensional conventional and three-dimensional patterned wafers, in March 2016. The Company has designed its equipment models for SAPS and TEBO solutions using a modular configuration that enables it to create a wet-cleaning tool meeting the specific requirements of a customer, while using pre-existing designs for chamber, electrical, chemical delivery and other modules. In 2018, the Company introduced its Ultra-C Tahoe wafer cleaning tool, which can deliver high cleaning performance with significantly less sulfuric acid than typically consumed by conventional high-temperature single-wafer cleaning tools. In 2020, the Company introduced a range of semi-critical cleaning systems, extending its products to support additional less demanding but still important production steps to semiconductor manufacturers. Based on its electro-chemical plating (“ECP”) technology, the Company introduced in 2019 its Ultra ECP ap, or “Advanced Packaging,” tool for bumping, or applying copper, tin and nickel to semiconductor wafers at the die-level, and its Ultra ECP map, or “Multi-Anode Partial Plating,” tool to deliver advanced electrochemical copper plating for copper interconnect applications in front-end wafer fabrication processes. In 2022, the Company added two major new product categories with the introduction of the Ultra Pmax™ PECVD and Ultra Track tools. The Company also offers a range of custom-made equipment, including cleaning, coaters and developers, to back-end wafer assembly and packaging factories, principally in mainland China. In November 2016, ACM re-domesticated from California to Delaware pursuant to a merger in which ACM Research, Inc., a California corporation, was merged into a newly formed, wholly-owned Delaware subsidiary, also named ACM Research, Inc. In November 2021, ACM Shanghai completed its STAR Listing and STAR IPO and its shares began trading on the STAR Market. In the STAR IPO, ACM Shanghai issued 43,355,753 shares, representing 10% of the total 433,557,100 shares outstanding after the issuance. The shares were issued at a public offering price of RMB 85.00 per share, and the net proceeds of the STAR IPO, after issuance costs, totaled $545,512. Upon completion of the STAR IPO, ACM owned 82.5% of the outstanding ACM Shanghai shares. However, in May 2023, ACM's ownership declined to 82.1% due to the exercise of 2,150,309 stock options related to ACM Shanghai shares. The Company has direct or indirect interests in the following subsidiaries: Effective interest held as at Name of subsidiaries Place and date of incorporation  Principal Activities March 31, 2024 December 31, 2023 ACM Research (Shanghai), Inc. ("ACM Shanghai") Mainland China, May 2005  Principal operating subsidiary 82.1  % 82.1  % ACM Research (Wuxi), Inc. ("ACM Wuxi") Mainland China, July 2011  Sales and services 82.1  % 82.1  % CleanChip Technologies Limited ("CleanChip") Hong Kong, June 2017  Trading partner between ACM Shanghai and its customers 82.1  % 82.1  % ACM Research Korea CO., LTD. Korea, December 2017  Sales, marketing, R&D, production 82.1  % 82.1  % ACM Research ( Lingang), Inc. ("ACM Lingang") (1) Mainland China, March 2019  Management of production activities 82.1  % 82.1  % ACM Research (CA), Inc. ("ACM California") USA, April 2019  Procurement for ACM Shanghai 82.1  % 82.1  % ACM Research (Cayman), Inc. Cayman Islands, April 2019  Administrative function (inactive) 100.0  % 100.0  % ACM Research (Singapore) PTE. Ltd. ("ACM Singapore") Singapore, August 2021  Sales, marketing, business development 100.0  % 100.0  % ACM Research (Beijing), Inc. ("ACM Beijing") Mainland China, February 2022  Sales, marketing, business development 82.1  % 82.1  % Hanguk ACM CO., LTD Korea, March 2022  Sales, services, business development 100.0  % 100.0  % Yusheng Micro Semiconductor (Shanghai) Co., Ltd. Mainland China, June 2023  Business development 82.1  % 82.1  % ACM-Wooil Microelectronics (Shanghai) Co., Ltd. Mainland China, June 2023  Component development and production 59.4  % 59.4  % (1) ACM Research (Lingang) Inc. is the English name referred to by its Chinese language name Shengwei Research (Shanghai), Inc., or ACM Shengwei in prior filings. ACM Research (Lingang), Inc. and Shengwei Research (Shanghai), Inc. refer to the same entity.

v3.24.1.u1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation and Principles of Consolidation The Company’s condensed consolidated financial statements include the accounts of ACM and its subsidiaries. ACM’s subsidiaries are those entities in which ACM, directly or indirectly, controls a majority of the voting power. All significant intercompany transactions and balances have been eliminated upon consolidation. The accompanying condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and the rules and regulations of the Securities and Exchange Commission (the “SEC”) for reporting on Form 10-Q. Accordingly, they do not include all the information and footnotes required by GAAP for complete financial statements. The accompanying condensed consolidated financial statements should be read in conjunction with the historical consolidated financial statements of the Company for the year ended December 31, 2023 included in ACM’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023. The accompanying condensed consolidated financial statements are unaudited. In the opinion of management, these unaudited condensed consolidated financial statements of the Company reflect all adjustments that are necessary for a fair presentation of the Company’s financial position and results of operations. Such adjustments are of a normal recurring nature, unless otherwise noted. The balance sheet as of March 31, 2024 and the results of operations for the three months ended March 31, 2024 are not necessarily indicative of the results to be expected for any future period. Use of Estimates The preparation of the condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the balance sheet date and the reported revenues and expenses during the reported period in the condensed consolidated financial statements and accompanying notes. The Company’s significant accounting estimates and assumptions include, but are not limited to, those used for revenue recognition and deferred revenue, the valuation and recognition of fair value of certain short-term investments and long-term investments, stock-based compensation arrangements, realization of deferred tax assets, assessment for impairment of long-lived assets and long-term investments, allowance for credit losses, inventory valuation, useful lives of property, plant and equipment and useful lives of intangible assets. Management evaluates these estimates and assumptions on a regular basis. Actual results could differ from those estimates and assumptions. Cash and Cash Equivalents Cash and cash equivalents consist of cash on hand, bank deposits that are unrestricted as to withdrawal and use, and highly liquid investments with an original maturity date of three months or less at the date of purchase. At times, cash deposits may exceed government-insured limits. The following table presents cash and cash equivalents, according to jurisdiction as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 United States $ 45,179  $ 43,614  Mainland China 101,590  70,418  China Hong Kong 63,401  64,057  Korea 1,068  3,934  Singapore 67  67  Total $ 211,305  $ 182,090  The amounts in mainland China do not include short-term and long-term time deposits which totaled $76,205 and $121,342 at March 31, 2024 and December 31, 2023, respectively. Cash held in the U.S. exceeds the Federal Deposit Insurance Corporation insurance limits and is subject to risk of loss. No losses have been experienced to date. Cash amounts held in mainland China are subject to a series of risk control regulatory standards from mainland China bank regulatory authorities. ACM’s subsidiaries in mainland China are required to obtain approval from the State Administration of Foreign Exchange (“SAFE”) to transfer funds into or out of mainland China. SAFE requires a valid agreement to approve the transfers, which are processed through a bank. Other than these mainland China foreign exchange restrictions, ACM’s subsidiaries in mainland China are not subject to any restrictions and limitations on its ability to transfer funds to ACM or among our other subsidiaries. However, cash held in mainland China does exceed applicable insurance limits and is subject to risk of loss, although no such losses have been experienced to date. ACM California periodically procures goods and services on behalf of ACM Shanghai. For these transactions, ACM Shanghai makes cash payments to ACM California in accordance with applicable transfer pricing arrangements. For the three months ended March 31, 2024 and 2023, cash payments from ACM Shanghai to ACM California for the procurement of goods and services was $4,648 and $10,931, respectively. ACM California periodically borrows funds for working capital advances from its direct parent, CleanChip. ACM California repays or renews these intercompany loans in accordance with their terms. For sales through CleanChip and ACM Research, a certain amount of sales or advanced payments from customers is repatriated back to ACM Shanghai in accordance with applicable transfer pricing arrangements in the ordinary course of business. ACM Research provides services to certain customers located in the U.S., Europe and other regions outside of mainland China to support the evaluation of first tools and provide support for tools under warranty on behalf of ACM Shanghai. For these transactions, ACM Shanghai makes cash payments to ACM Research in accordance with applicable transfer pricing arrangements. Amounts held in Korea exceed the Korea Deposit Insurance Corporation insurance limits and is subject to risk of loss. No losses have been experienced to date. There is no additional restriction for the transfer of cash from bank accounts in the U.S., Korea, Singapore and Hong Kong. For the three months ended March 31, 2024 and 2023, with the exception of sales and services-related transfer-pricing payments in the ordinary course of business, no transfers, or distributions have been made between ACM Research and its subsidiaries, including ACM Shanghai, or to holders of ACM Research Class A common stock. Time Deposits Time deposits are deposited with banks in mainland China with fixed terms and interest rates which cannot be withdrawn before maturity, and are presented as short-term deposits and long-term deposits in the condensed consolidated financial statements based on their expected time of collection. They are also subject to the risk control regulatory standards described above upon maturity. At March 31, 2024 and December 31, 2023, time deposits consisted of the following: March 31, 2024 December 31, 2023 Deposit in China Merchant Bank which matured on January 29, 2024 with an annual interest rate of 2.85% $ —  $ 29,797  Deposit in Bank of Ningbo which matured on February 17, 2024 with an annual interest rate of 2.85% $ —  $ 44,630  Deposit in Shanghai Pudong Development Bank which matures on October 20, 2025 with an annual interest rate of 3.10% $ 7,361  $ 7,322  Deposit in Shanghai Pudong Development Bank which matures on November 14, 2025 with an annual interest rate of 3.10% $ 4,407  $ 7,307  Deposit in Shanghai Pudong Development Bank which matures on December 8, 2025 with an annual interest rate of 3.10% $ —  $ 4,376  Deposit in Shanghai Pudong Development Bank which matures on December 15, 2025 with an annual interest rate of 3.10% $ 1,465  $ 4,373  Deposit in Shanghai Pudong Development Bank which matures on December 30, 2025 with an annual interest rate of 3.10% $ —  $ 2,912  Deposit in China Industrial Bank which matures on January 3, 2026 with an annual interest rate of 3.15% $ 14,608  $ 14,528  Deposit in China Everbright Bank which matures on December 5, 2024 with an annual interest rate of 5.38% $ —  $ 3,079  Deposit in China Everbright Bank which matures on May 22, 2024 with an annual interest rate of 5.28% $ 3,057  $ 3,018  Deposit in China Everbright Bank which matured on April 5, 2024 with an annual interest rate of 5.33% $ 3,037  $ —  Deposit in China Merchant Bank, Lujiazui Branch which matures on May 27, 2024 with an annual interest rate of 1.85% $ 14,090  $ —  Deposit in China Merchant Bank, Huaihai Branch which matures on May 27, 2024 with an annual interest rate of 1.85% $ 14,090  $ —  Deposit in Bank of Ningbo which matures on September 11, 2024 with an annual interest rate of 1.50% $ 14,090  $ —  $ 76,205  $ 121,342  For the three months ended March 31, 2024 and 2023, interest income related to time deposits was $624 and $975, respectively. Financial Instruments The Company periodically invests in equity securities, and maintains an investment portfolio of various holdings, types, and maturities. For equity investments that do not have a readily determinable fair value, the Company classified them as long-term investments, and records them using either: 1) the measurement alternative which measures the equity investments at cost minus impairment, if any, plus or minus changes resulting from qualifying observable price changes; or 2) the equity method whereby the Company recognizes its proportional share of the income or loss from the equity method investment. The equity method is utilized when the equity investments are common stock or in substance common stock, and the Company does not have the ability to control the investee but is deemed to have the ability to exercise significant influence over the investee’s operating or financial policies. For equity investments that have a readily determinable fair value, the Company classified them as short-term investments, and records them at fair market value on a recurring basis based upon quoted market prices. Realized and unrealized gains and losses resulting from application of the measurement alternative, the impact of the application of the equity method to the Company’s equity investments, and recognition of changes in fair market value, as applicable, are recognized as non-operating income (expenses), net in the condensed consolidated statements of comprehensive income. The Company defines fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, the Company considers the principal or most advantageous market in which it would transact, and it considers assumptions that market participants would use when pricing the asset or liability. A fair value hierarchy has been established that prioritizes the inputs to valuation techniques used to measure fair value. The level of an asset or liability in the hierarchy is based on the lowest level of input that is significant to the fair value measurement. Assets and liabilities carried at fair value are classified and disclosed in one of the following three categories: Level 1: Valuations based on quoted prices in active markets for identical assets or liabilities with sufficient volume and frequency of transactions. Level 2: Valuations based on observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active for identical assets or liabilities, or model-derived valuations techniques for which all significant inputs are observable in the market or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3: Valuations based on unobservable inputs to the valuation methodology that are significant to the measurement of fair value of assets or liabilities and based on non-binding, broker-provided price quotes and may not have been corroborated by observable market data. The Company’s primary financial instruments include its cash, cash equivalents, short term and long term deposits, restricted cash, short-term and long-term investments, other receivables, accounts receivable, accounts payable, and short-term and long-term borrowings. The estimated fair value of cash and cash equivalents, short-term time deposits, accounts receivable, other receivables, accounts payable, and short-term borrowings approximates their carrying value due to the short period of time to their maturities. All transfers between fair value hierarchy levels are recognized by the Company at the end of each reporting period. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement in its entirety, requires judgment and considers factors specific to the investment. The inputs or methodology used for valuing financial instruments are not necessarily an indication of the risks associated with investment in those instruments. Assets and liabilities measured at fair value on a recurring basis: Quoted Prices in Active Markets for Identical Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total As of March 31, 2024: Assets      Cash and cash equivalents $ 36,509  $ —  $ —  $ 36,509       Short-term investments 18,648  —  —  18,648  $ 55,157  $ —  $ —  $ 55,157  As of December 31, 2023: Assets      Cash and cash equivalents $ 37,518  $ —  $ —  $ 37,518       Short-term investments 21,312  —  —  21,312  $ 58,830  $ —  $ —  $ 58,830  Assets and liabilities measured at fair value on a non-recurring basis:  Quoted Prices in Active Markets for Identical Liabilities (Level 1)  Significant Other Observable Inputs (Level 2)  Significant Unobservable Inputs (Level 3)  Total  As of December 31, 2023:  Assets Investments accounted for using measurement alternative $ —  $ —  $ 10,378  $ 10,378  $ —  $ —  $ 10,378  $ 10,378  The Company did not have any assets and liabilities measured at fair value on a non-recurring basis as of March 31, 2024, and the Company did not recognize any unrealized gains (upward adjustments) or unrealized losses (downward adjustments) resulting from observable price changes in orderly transactions for an identical or similar investment of the same issuer for its long-term investments accounted for using measurement alternatives during the three months ended March 31, 2024 and 2023. Refer to Note 12 for fair value information related to the Company’s outstanding long-term borrowings as of March 31, 2024 and December 31, 2023. Basic and Diluted Net Income per Share of Common Stock Basic and diluted net income per share of common stock are calculated as follows: Three Months Ended March 31, 2024 2023 Numerator:        Net income $ 22,092  $ 8,963         Less: Net income attributable to non-controlling interests 4,659  1,818  Net income available to common stockholders, basic $ 17,433  $ 7,145         Less: Dilutive effect arising from stock-based awards by ACM Shanghai 354  93  Net income available to common stockholders, diluted $ 17,079  $ 7,052  Weighted average shares outstanding, basic 61,367,184 59,736,764        Effect of dilutive securities 4,875,137 5,322,013        Weighted average shares outstanding, diluted 66,242,321 65,058,777 Net income per share of common stock: Basic $ 0.28  $ 0.12  Diluted $ 0.26  $ 0.11  Basic and diluted net income per share of common stock is presented using the two-class method, which allocates undistributed earnings to common stock and any participating securities according to dividend rights and participation rights on a proportionate basis. Under the two-class method, basic net income per share of common stock is computed by dividing the sum of distributed and undistributed earnings attributable to common stockholders by the weighted average number of shares of common stock outstanding during the period. ACM Research did not have any participating securities outstanding during the three months ended March 31, 2024 and 2023. ACM Research has been authorized to issue Class A and Class B common stock since redomesticating in Delaware in November 2016. The two classes of common stock are substantially identical in all material respects, except for voting rights. Since ACM Research did not declare any cash dividends during the three months ended March 31, 2024 or 2023, the net income per share of common stock attributable to each class is the same under the “two-class” method. As such, the two classes of common stock have been presented on a combined basis in the condensed consolidated statements of comprehensive income and in the above computation of net income per share of common stock. Diluted net income per share of common stock reflects the potential dilution from securities, such as stock options that could share in ACM Research’s earnings. Certain potential dilutive securities were excluded from the net income per share calculation because the impact would be anti-dilutive. The number of potentially dilutive shares that were not included in the calculation of diluted net income per share in the periods presented where their inclusion would be anti-dilutive were 728,575 and 1,967,685 stock options for the three months ended March 31, 2024 and 2023, respectively. Concentration of Credit Risk Financial instruments that potentially subject the Company to credit risk consist principally of cash and cash equivalents, time deposits, and accounts receivable. The Company deposits and invests its cash and cash equivalents and time deposits with financial institutions that management believes are creditworthy. The Company is potentially subject to concentrations of credit risks in its revenue and accounts receivable. For the three months ended March 31, 2024 and 2023, two customers accounted for 55.9% and four customers accounted for 59.7% of revenue, respectively. As of March 31, 2024 and December 31, 2023, four customers accounted for 56.2% and four customers accounted for 59.1%, respectively, of the Company’s accounts receivables. The Company believes that the receivable balances from these largest customers do not represent a significant credit risk based on past collection experience. Recently issued accounting pronouncements not yet adopted In November 2023, the FASB issued ASU No. 2023-07, Improvements to Reportable Segment Disclosures. This ASU updates reportable segment disclosure requirements by requiring disclosures of significant reportable segment expenses that are regularly provided to the Chief Operating Decision Maker (“CODM”) and included within each reported measure of a segment's profit or loss. This ASU also requires disclosure of the title and position of the individual identified as the CODM and an explanation of how the CODM uses the reported measures of a segment’s profit or loss in assessing segment performance and deciding how to allocate resources. The ASU is effective for annual periods beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Adoption of the ASU should be applied retrospectively to all prior periods presented in the financial statements. Early adoption is also permitted. The Company is currently evaluating the provisions of this ASU and expect to adopt it for the year ending December 31, 2024. In December 2023, the FASB issued ASU No. 2023-09, Improvements to Income Tax Disclosures (Topic 740). The ASU requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as additional information on income taxes paid. The ASU is effective on a prospective basis for annual periods beginning after December 15, 2024. Retrospective application is permitted. Early adoption is also permitted for annual financial statements that have not yet been issued or made available for issuance. The Company is currently evaluating the provisions of this ASU.

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REVENUE FROM CONTRACTS WITH CUSTOMERS	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
REVENUE FROM CONTRACTS WITH CUSTOMERS	REVENUE FROM CONTRACTS WITH CUSTOMERS The Company assesses revenues based upon the nature or type of goods or services it provides and the geographic location of the customer facility. The following tables present disaggregated revenue information: Three Months Ended March 31, 2024 2023 Single Wafer Cleaning, Tahoe and Semi-Critical Cleaning Equipment $ 109,470  $ 36,614  ECP (front-end and packaging), Furnace and Other Technologies 25,800  26,598  Advanced Packaging (excluding ECP), Services & Spares 16,921  11,044  Total Revenue by Product Category $ 152,191  $ 74,256  Three Months Ended March 31, 2024 2023 Mainland China $ 152,135  $ 72,458  Other regions 56  1,798  $ 152,191  $ 74,256  Below are the accounts receivables and contract liabilities balances as of: March 31, 2024 December 31, 2023       Accounts receivable 296,371  283,186        Advances from customers 182,547  181,368         Deferred revenue 4,405  3,687  During the three months ended March 31, 2024, advances from customers increased by $1.2 million, due to an increase of payments made by customers for first tools under evaluation, offset by a decrease in customer pre-payments for tools prior to delivery. Below are revenues recognized from amounts included in contract liabilities at the beginning of the year: Three Months Ended March 31, 2024 2023 Revenue recognized from amounts included in contract liabilities at the beginning of the year $ 29,188  $ 15,212

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ACCOUNTS RECEIVABLE	3 Months Ended
	Mar. 31, 2024
Receivables [Abstract]
ACCOUNTS RECEIVABLE	ACCOUNTS RECEIVABLE At March 31, 2024 and December 31, 2023, accounts receivable consisted of the following: March 31, 2024 December 31, 2023 Accounts receivable $ 302,372  $ 288,016  Less: Allowance for credit losses (6,001) (4,830) $ 296,371  $ 283,186  The $13.2 million increase in accounts receivable for the first three months of 2024 corresponds to a $77.9 million increase in revenue for the same period. The movement of the allowance for credit losses for the three months ended March 31, 2024 is as follows: Allowance for credit losses, before tax, as of January 1 Provision for credit losses Allowance for credit losses, before tax, as of March 31 March 31, 2024 $ (4,830) (1,171) $ (6,001) The Company assesses collectability by reviewing accounts receivable on a general basis where similar characteristics exist and on an individual basis when the Company identifies specific customers with known disputes or collectability issues. In determining the amount of the allowance for credit losses, the Company considers historical collectability based on past due status, the age of the accounts receivable balances, credit quality of the Company’s customers based on ongoing credit evaluations, current economic conditions, reasonable and supportable forecasts of future economic conditions, and other factors that may affect the Company’s ability to collect from customers.

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INVENTORIES	3 Months Ended
	Mar. 31, 2024
Inventory Disclosure [Abstract]
INVENTORIES	INVENTORIES At March 31, 2024 and December 31, 2023, inventories consisted of the following: March 31, 2024 December 31, 2023 Raw materials $ 256,332  $ 235,062  Work-in-process 61,871  81,438  Finished goods 262,937  228,895  Total inventory $ 581,140  $ 545,395  At March 31, 2024 and December 31, 2023, the value of finished goods inventory of which were first-tools at customer physical locations for which customers were contractually obligated to take ownership upon acceptance totaled $163,484 and $123,390, respectively. The $21,270 increase in raw materials at March 31, 2024 compared to December 31, 2023 was due to additional purchase of supplies to support a higher level of expected total shipments for the next several quarters, and to reduce the risk of supply chain delays to meet anticipated customer demand for the Company’s products. The $34,042 increase in finished goods inventory at March 31, 2024 compared to December 31, 2023 reflects a higher value of first-tools under evaluation by existing or prospective customers, due to shipments made, net of customer acceptances during the period. The Company’s products each require a certain degree of customization, and the substantial majority of the work-in-process inventory and finished goods inventory is built to meet a specific customer order for a repeat shipment or a first tool shipment. At the end of each period, the Company assesses the status of each item in work-in-process and finished goods inventory. The Company recognizes a loss or impairment if in management’s judgement the inventory cannot be sold or used for production, if it has been damaged or should be considered as obsolete, or if the net realizable value is lower than the cost. At the end of each period, the Company also assesses the status of its raw materials. The Company recognizes a loss or impairment for any raw materials aged more than three years. The three-year aging is based on the Company’s assessment of technology change, its requirement to maintain stock for warranty coverage, and other factors. During the three months ended March 31, 2024 and 2023, provision for inventory of $1,025 and $306 were recognized in cost of revenue, respectively. Write-downs were due to an internal assessment that certain inventory could not be sold or used for production due to damage or obsolescence.

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PROPERTY, PLANT AND EQUIPMENT, NET	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT, NET	PROPERTY, PLANT AND EQUIPMENT, NET At March 31, 2024 and December 31, 2023, property, plant and equipment consisted of the following: March 31, 2024 December 31, 2023 Buildings and plants $ 82,933  $ 83,109  Manufacturing equipment 16,702  16,556  Office equipment 5,061  4,953  Transportation equipment 402  404  Leasehold improvement 7,961  7,889  Total cost 113,059  112,911  Less: Total accumulated depreciation and amortization (19,531) (17,503) Construction in progress 125,294  106,440  Total property, plant and equipment, net $ 218,822  $ 201,848  Depreciation expense for the three months ended March 31, 2024 and 2023 was $2,475 and $1,714, respectively. Buildings and plants represent Lingang housing property owned by ACM Liangang at a value of RMB 249,746 ($35,189), and facilities for the new headquarters of ACM Shanghai ("Zhangjiang New Building") at a value of RMB 338,848 ($47,744), as of March 31, 2024. The Lingang housing property is pledged as security for loans from China Merchants Bank (Note 12). Construction in progress primarily reflects costs incurred related to the construction of ACM Shanghai’s Lingang development and production center, and is scheduled to begin production in the second half of 2024.

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LAND USE RIGHT, NET	3 Months Ended
	Mar. 31, 2024
Land Use Right, Net [Abstract]
LAND USE RIGHT, NET	LAND USE RIGHT, NET A summary of land use right is as follows: March 31, 2024 December 31, 2023 Land use right purchase amount $ 8,977  $ 8,996  Less: accumulated amortization (672) (629) Land use right, net $ 8,305  $ 8,367  The amortization for the three months ended March 31, 2024 and 2023 was $43 and $50, respectively. The annual amortization of land use right is as follows: Year ending December 31, remainder of 2024 $ 135  2025 180  2026 180  2027 180  2028 180  2029 and thereafter 7,450  Total $ 8,305

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OTHER LONG-TERM ASSETS	3 Months Ended
	Mar. 31, 2024
Other Assets, Noncurrent Disclosure [Abstract]
OTHER LONG-TERM ASSETS	OTHER LONG-TERM ASSETS At March 31, 2024 and December 31, 2023, other long-term assets consisted of the following: March 31, 2024 December 31, 2023 Prepayments for property, plant and equipment $ 7,690  $ 3,380  Lease deposits 867  834  Security deposit for land use right 695  696  Others 1,219  1,140  Total other long-term assets $ 10,471  $ 6,050

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SHORT-TERM BORROWINGS	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
SHORT-TERM BORROWINGS	SHORT-TERM BORROWINGS At March 31, 2024 and December 31, 2023, short-term borrowings consisted of the following: March 31, 2024 December 31, 2023 Line of credit up to RMB 150,000 from China Everbright Bank, 1)due on August 29, 2024 with an annual interest rate of 3.00%. 2,459  2,463  Line of credit up to RMB 40,000 from Bank of China, 1)due on September 7, 2024 with an annual interest rate of 2.87%. 5,640  5,648  Line of credit up to RMB 200,000 from China Merchants Bank, 1)due on August 7, 2024 with an annual interest rate of 3.00%. 1,269  1,271  2)due on August 8, 2024 with an annual interest rate of 3.00%. 1,269  1,271  3)due on August 9, 2024 with an annual interest rate of 3.00%. 1,269  1,271  4)due on August 14, 2024 with an annual interest rate of 3.00%. 1,269  1,271  5)due on August 17, 2024 with an annual interest rate of 3.00%. 1,269  1,271  6)due on August 20, 2024 with an annual interest rate of 3.00%. 1,269  1,271  7)due on August 21, 2024 with an annual interest rate of 3.00%. 1,269  1,271  8)due on August 22, 2024 with an annual interest rate of 3.00%. 1,269  1,271  9)due on August 24, 2024 with an annual interest rate of 3.00%. 1,269  1,271  10)due on August 27, 2024 with an annual interest rate of 3.00%. 1,269  1,271  11)due on August 29, 2024 with an annual interest rate of 3.00%. 1,269  1,271  12)due on August 30, 2024 with an annual interest rate of 3.00%. 1,269  1,271  13)due on September 3, 2024 with an annual interest rate of 3.00%. 1,269  1,271  14)due on September 5, 2024 with an annual interest rate of 3.00%. 1,269  1,270  15)due on September 6, 2024 with an annual interest rate of 3.00%. 1,269  1,270  16)due on September 10, 2024 with an annual interest rate of 3.00%. 1,269  1,270  17)due on September 12, 2024 with an annual interest rate of 3.00%. 1,269  1,270  18)due on February 27, 2025 with an annual interest rate of 2.60%. 1,340  —  19)due on February 28, 2025 with an annual interest rate of 2.60%. 1,340  —  20)due on March 1, 2025 with an annual interest rate of 2.60%. 1,340  —  21)due on March 5, 2025 with an annual interest rate of 2.60%. 1,340  —  22)due on March 8, 2025 with an annual interest rate of 2.60%. 1,270  —  Line of credit up to RMB 120,000 from Bank of China, 1)due on March 20, 2025 with an annual interest rate of 2.75%. 16,921  —  Line of credit up to KRW 500,000 from Industrial Bank of Korea, 1)due on July 12, 2024 with an annual interest rate of 6.03%. —  77  Line of credit up to KRW 2,000,000 from Industrial Bank of Korea, 1)due on December 15, 2024 with an annual interest rate of 4.27%. 1,483  1,544  Total $ 54,706  $ 31,335  For the three months ended March 31, 2024 and 2023, interest expense related to short-term borrowings amounted to $213 and $490, respectively.

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OTHER PAYABLES AND ACCRUED EXPENSES	3 Months Ended
	Mar. 31, 2024
Payables and Accruals [Abstract]
OTHER PAYABLES AND ACCRUED EXPENSES	OTHER PAYABLES AND ACCRUED EXPENSES At March 31, 2024 and December 31, 2023, other payables and accrued expenses consisted of the following: March 31, 2024 December 31, 2023 Accrued commissions $ 15,932  $ 15,572  Accrued warranty 11,339  9,834  Accrued payroll 16,550  14,840  Accrued professional fees 113  696  Accrued machine testing fees 1,863  1,762  Accrued machine sales fees 4,942  6,010  Accrued Lingang construction fees 33,546  33,729  Others 22,813  20,508  Total $ 107,098  $ 102,951

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LEASES	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
LEASES	LEASES The Company leases space under non-cancelable operating leases for several offices and manufacturing locations. These leases do not have significant rent escalation holidays, concessions, leasehold improvement incentives, or other build-out clauses. Further, the leases do not contain contingent rent provisions. Most leases include one or more options to renew. The Company regularly evaluates the renewal options, and when they are reasonably certain of exercise, the Company includes the renewal period in its lease term. The components of lease expense were as follows: Three Months Ended March 31, 2024 2023 Operating lease cost $ 973  $ 488  Short-term lease cost 321  282  Total lease cost $ 1,294  $ 770  Supplemental cash flow information related to operating leases was as follows: Three Months Ended March 31, 2024 2023      Operating cash outflow from operating leases $ 973  $ 488      Operating lease right-of-use assets obtained in exchange for new operating lease liabilities $ 80  $ 6,592  As of March 31, 2024, maturities of outstanding lease liabilities for all operating leases were as follows: December 31, remainder of 2024 $ 2,370  2025 1,800  2026 1,215  2027 1,148  2028 and thereafter 595  Total lease payments $ 7,128  Less: Interest (630) Present value of lease liabilities $ 6,498  The weighted average remaining lease terms and discount rates for all operating leases were as follows: March 31, 2024 December 31, 2023 Remaining lease term and discount rate: Weighted average remaining lease term (years) 3.37 3.44 Weighted average discount rate 3.87  % 3.91  %

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LONG-TERM BORROWINGS	3 Months Ended
	Mar. 31, 2024
Long-Term Debt, by Current and Noncurrent [Abstract]
LONG-TERM BORROWINGS	LONG-TERM BORROWINGS At March 31, 2024 and December 31, 2023, long-term borrowings consisted of the following: March 31, 2024 December 31, 2023 Loan from China Merchants Bank $ 12,919  $ 13,362  Loans from Bank of China 4,759  5,013  Loan from Bank of Shanghai 14,101  14,120  Loan from China CITIC Bank 28,178  28,240  Less: Current portion (6,549) (6,783) Total $ 53,408  $ 53,952  The loan from China Merchants Bank is for the purpose of purchasing housing property in Lingang, Shanghai. The loan is repayable in 120 total installments with the last installment due in November 2030, with an annual interest rate of 3.95%. The loan is pledged by the property of ACM Lingang and guaranteed by ACM Shanghai. Two loans from Bank of China are for the purpose of funding ACM Shanghai project expenditures. The loans bear interest at an annual rate of 2.6% and are repayable in 6 installments, with the last installments due in June 2024 and September 2024, respectively. The loan from Bank of Shanghai is for the purpose of funding ACM Shanghai project expenditures. The loan bears interest at an annual rate of 2.85%, and will be fully repaid in April 2025. The first loan from China CITIC Bank is for the purpose of funding ACM Shanghai project expenditures. The loan bears interest at an annual rate of 3.1% and is repayable in 4 installments, with the last installment due in August 2025. The second loan from China CITIC bank is for the purpose of funding ACM's general corporate expenses and working capital. The loan bears interest at an annual rate of 4.50% payable quarterly, and the principal amount is repayable in 4 installments, with the last installment due in December 2025. As of March 31, 2024 and December 31, 2023, the total carrying amount of long-term loans was $59,957 and $60,735, compared with an estimated fair value of $56,409 and $56,462, respectively. The fair value of the long-term loans is estimated by discounting cash flows using interest rates currently available for debts with similar terms and maturities (Level 2 fair value measurement). Refer to Note 2 for an explanation of the fair value hierarchy structure. Scheduled principal payments for the outstanding long-term loan, including the current portion, as of March 31, 2024 are as follows: Year ending December 31 remainder of 2024 $ 6,120  2025 43,993  2026 1,851  2027 1,925  2028 2,003  Thereafter 4,065  $ 59,957  For the three months ended March 31, 2024 and 2023, respectively, interest related to long-term borrowings of $570 and $189 was incurred, and all of them were charged to interest expenses

v3.24.1.u1

OTHER LONG-TERM LIABILITIES	3 Months Ended
	Mar. 31, 2024
Other Liabilities Disclosure [Abstract]
OTHER LONG-TERM LIABILITIES	OTHER LONG-TERM LIABILITIES Other long-term liabilities represent government subsidies received from mainland China governmental authorities for development and commercialization of certain technology but not yet recognized. At March 31, 2024 and December 31, 2023, other long-term liabilities consisted of the following unearned government subsidies: March 31, 2024 December 31, 2023 Subsidies to Stress Free Polishing project, commenced in 2008 and 2017 $ 189  $ 475  Subsidies to other cleaning tools, commenced in 2020 647  632  Subsidies to SW Lingang R&D development in 2021 3,454  3,467  Other 1,179  1,299  Total $ 5,469  $ 5,873

v3.24.1.u1

LONG-TERM INVESTMENT	3 Months Ended
	Mar. 31, 2024
Long-Term Investments [Abstract]
LONG-TERM INVESTMENT	LONG-TERM INVESTMENTS On January 12, 2024, ACM Shanghai entered into an investment agreement with Company C to invest RMB 12,500 ($1,760), which represented 0.3% of the Company C's total equity interest. Since there is no readily determinable fair value, the Company measures the investments at measurement alternative. On January 19, 2024, ACM Shanghai entered into a limited partnership agreement with Company D to invest RMB 30,000 ($4,230), which represented 16.7% of the partnership's total equity interest. The investment in the limited partnership with Company D is accounted for under the equity method in accordance with ASC323-30-S99-1. Equity investee: Initial investment dates Investment entity Percent ownership by ACM and subsidiaries Investment purchase price Ninebell Co., Ltd. ("Ninebell") September 2017 ACM 20.0% $ 1,200  Shengyi Semiconductor Technology Co., Ltd. ("Shengyi") June 2019 ACM Shanghai 14.0% $ 109  Hefei Shixi Chanheng Integrated Circuit Industry Venture Capital FundPartnership (LP) (“Hefei Shixi”) September 2019 ACM Shanghai 10.0% RMB 30,000 ($4,200) Wooil Flucon Co. ("Wooil") August 2022 ACM Singapore 20.0% $ 1,000  Company D February 2024 ACM Shanghai 16.7% RMB 30,000 ($4,230) Investments accounted for using measurement alternative: Waferworks (Shanghai) Co., Ltd. (“Waferworks”) October 2021 ACM Shanghai 0.3% $ 1,568  Company A September 2023 ACM Shanghai 4.4% RMB 30,000 ($4,200) Shengyi September 2023 ACM Shanghai 1.0% RMB 6,100 ($860) Company B November 2023 ACM Shanghai 1.4% RMB 6,600 ($930) Company C February 2024 ACM Shanghai 5.0% RMB 12,500 ($1,760) Equity investee: March 31, 2024 December 31, 2023 Ninebell $ 5,481  $ 5,632  Wooil 989  1,003  Shengyi 1,999  1,693  Hefei Shixi 7,888  9,174  Company D 4,227  —  Subtotal 20,584  17,502  Investments accounted for using measurement alternative: Waferworks —  1,412  Shengyi 856  857  Company A 4,227  4,236  Company B 930  932  Company C 1,761  —  Other 2,935  2,941  Total 31,293  27,880  For the three months ended March 31, 2024 and 2023, the Company’s share of equity investees’ net loss was $520 and $32, respectively, which amounts were included in loss from equity method investments in the accompanying condensed consolidated statements of comprehensive income. For the three months ended March 31, 2024 and 2023, the Company received $600 and $0 dividends from equity investee.

v3.24.1.u1

SHORT-TERM INVESTMENTS	3 Months Ended
	Mar. 31, 2024
Investments, Debt and Equity Securities [Abstract]
SHORT-TERM INVESTMENTS	SHORT-TERM INVESTMENTS Pursuant to an Agreement entered into on September 19, 2022 (the ‘‘Agreement’’), ACM Shanghai became a limited partner of the Nuode Asset Fund Pujiang No. 783 Single Asset Management Plan (‘‘Nuode Asset Fund’’), a Chinese limited partnership formed by Nuode Asset Management Co., Ltd, a financial services firm based in Shanghai, China. Nuode Asset Fund was formed to establish a special fund with the purpose to participate in certain technology related investments in mainland China. Subsequent to the future purchase, any investment will be held by Nuode Asset Fund and restricted for a minimum period of nine months. The limited partners of the Nuode Asset Fund contributed a total RMB 160 million ($22,160) to the fund, of which ACM Shanghai contributed RMB 30 million ($4,196), or 18.75% of the contribution on September 27, 2022. In December 2022, the Nuode Asset Fund purchased shares in the secondary stock offering of a publicly traded mainland China-stock listing. The number of shares owned by Nuode Asset Fund was apportioned to all of the limited partners in proportion to their respective capital contributions which is 18.75% in the case of ACM Shanghai. The investments were fully disposed in the three months ended March 31, 2024 and the Company has not received the proceeds as of March 31, 2024 with a receivable of RMB 22,478 ($3,167) was recorded. Pursuant to a Share Purchase Agreement dated June 2023, ACM Shanghai acquired shares of Huahong Semiconductor Limited (“Huahong”) in July 2023 with amount of RMB 100 million ($13,930). The shares held by ACM Shanghai are restricted for sale for a minimum period of twelve months. Huahong completed its STAR IPO in August 2023. Pursuant to a Share Purchase Agreement dated August 2023, ACM Shanghai acquired shares of Zhongjuxin Limited Company (“Zhongjuxin”) in September 2023 with amount of RMB 30 million ($4,179). The shares held by ACM Shanghai are restricted for sale for a minimum period of twelve months. Zhongjuxin completed its STAR IPO in September 2023. Pursuant to a Share Purchase Agreement dated January 2024, ACM Shanghai acquired shares of Shanghai Syncrystalline Silicon Materials Co., Ltd. (“Syncrystalline”) in February 2024 with amount of RMB 10,000 ($1,409). The shares held by ACM Shanghai are restricted for sale for a minimum period of twelve months. Syncrystalline completed its STAR IPO in February 2024. As of March 31, 2024, the Company's total investment costs in Syncrystalline were RMB 20,000($2,818), including RMB 10,000 ($1,409) invested by ACM Shanghai in 2021 and RMB 10,000 ($1,409) invested by ACM Shanghai in February 2024. At March 31, 2024 and December 31, 2023, the components of short-term investments were as follows: March 31, 2024 December 31, 2023 Short-term investments listed in Shanghai Stock Exchange   Cost $ 21,135  $ 20,155    Market value 18,648  21,312  For the three months ended March 31, 2024 and 2023, the net gains (losses) recognized on equity securities were as follows: Three Months Ended March 31, 2024 2023 Unrealized losses recognized during the reporting period on equity securities still held at March 31 $ (2,595) $ (654) Net gains recognized during the period on equity securities sold during the period $ 273  $ 3,994  Total net gains (losses) recognized at March 31 on equity securities $ (2,322) $ 3,340  For the three months ended March 31, 2024, the Company recognized a receivable of RMB 22,478 ($3,167) from the sales of short-term investments, including a realized gain of $273. For the three months ended March 31, 2023, the Company received $11,072 in proceeds from the sale of short-term investments, including a realized gain of $3,994.

v3.24.1.u1

RELATED PARTY BALANCES AND TRANSACTIONS	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
RELATED PARTY BALANCES AND TRANSACTIONS	RELATED PARTY BALANCES AND TRANSACTIONS Ninebell Ninebell is an equity investee of ACM (Note 14) and is the Company’s principal supplier of robotic delivery system subassemblies used in our single-wafer cleaning equipment. The Company purchases equipment from Ninebell for production in the ordinary course of business. The Company pays for a portion of the equipment in advance and is obligated for the remaining amounts upon receipt of the product. Shengyi Shengyi is an equity investee of ACM Shanghai (Note 14) and is one of the Company’s component suppliers in mainland China. The Company purchases components from Shengyi for production in the ordinary course of business. The Company incurs a service fee related to installation and hook-up fees which is recorded within cost of revenue on the Company’s condensed consolidated statements of comprehensive income. The Company pays for a portion of the raw materials in advance and is obligated for the remaining amounts upon receipt of the product. All related party outstanding balances are short-term in nature and are expected to be settled in cash. The following tables reflect related party transactions in our condensed consolidated financial statements: Advances to related party March 31, 2024 December 31, 2023 Ninebell $ 1,338  $ 2,432  Accounts payable March 31, 2024 December 31, 2023 Ninebell $ 12,571  $ 7,624  Shengyi 3,672  3,783  Total $ 16,243  $ 11,407  Three Months Ended March 31, Purchase of materials 2024 2023 Ninebell $ 14,152  $ 16,397  Shengyi 992  1,973  Total $ 15,144  $ 18,370  Three Months Ended March 31, Service fee charged by 2024 2023 Shengyi $ 73  $ 278

v3.24.1.u1

COMMON STOCK	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
COMMON STOCK	COMMON STOCK ACM is authorized to issue 150,000,000 shares of Class A common stock and 5,307,816 shares of Class B common stock, each with a par value of $0.0001. Each share of Class A common stock is entitled to one vote, and each share of Class B common stock is entitled to twenty votes and is convertible at any time into one share of Class A common stock. Shares of Class A common stock and Class B common stock are treated equally, identically and ratably with respect to any dividends declared by the Board of Directors of ACM unless such Board of Directors declares different dividends to the Class A common stock and Class B common stock, which is subject to approval from a majority of common stockholders. During the three months ended March 31, 2024, ACM issued 950,605 shares of Class A common stock upon option exercises by employees and non-employees. During the three months ended March 31, 2023, ACM issued 163,069 shares of Class A common stock upon option exercises by employees and non-employees. At March 31, 2024 and December 31, 2023, the number of shares of Class A common stock issued and outstanding was 56,986,777 and 56,036,172, respectively. At March 31, 2024 and December 31, 2023, the number of shares of Class B common stock issued and outstanding was 5,021,811 and 5,021,811, respectively.

v3.24.1.u1

STOCK-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION ACM’s stock-based compensation consists of employee and non-employee awards issued under its 1998 Stock Option Plan and its 2016 Omnibus Incentive Plan. The vesting condition may consist of a service period condition determined by the Board of Directors for a grant or certain performance conditions determined by the Board of Directors for a grant. The fair value of the stock options granted with a service period based condition and/or performance condition is estimated at the date of grant using the Black-Scholes option pricing model. The fair value of the stock options granted with a market based condition is estimated at the date of grant using the Monte Carlo simulation model. Employee Awards The following table summarizes the Company’s employee share option activities during the three months ended March 31, 2024: Number of  Option Shares Weighted  Average Grant Date Fair Value Weighted Average Exercise Price Weighted Average Remaining Contractual Term Outstanding at December 31, 2023 9,998,637 $ 5.15  $ 9.59  6.17 years Granted 3,000 23.95 31.92  Exercised (851,954) 2.7 5.74  Forfeited/cancelled (24,330) 11.14 23.08  Outstanding at March 31, 2024 9,125,353 $ 5.37  $ 9.79  6.07 years Vested and exercisable at March 31, 2024 5,278,784 As of March 31, 2024 and December 31, 2023, $24,670 and $27,152, respectively, of total unrecognized employee stock-based compensation expense, net of estimated forfeitures, related to employee stock-based awards for ACM were expected to be recognized over a weighted-average period of 3.8 years and 4.0 years, respectively. Total recognized compensation cost may be adjusted for future changes in estimated forfeitures. The aggregate intrinsic value of options exercised in the three months ended March 31, 2024 was $21,865. The aggregate intrinsic value of options outstanding and exercisable as of March 31, 2024 were $178,674 and $117,476, respectively. The fair value of options granted to employees is estimated on the grant date using the Black-Scholes valuation with following assumptions: Three Months Ended March 31, 2024 Fair value of common share(1) 31.92 Expected term in years(2) 6.25 Volatility(3) 85.48% Risk-free interest rate(4) 4.23% Expected dividend (5) —% (1)Fair value of Class A common stock value was closing market price of the Class A common stock on the grant date. (2)Expected term of share options is based on the average of the vesting period and the contractual term for each grant. (3)Volatility is calculated based on the historical volatility of ACM in the period equal to the expected term of each grant. (4)Risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected term of the share options in effect at the time of grant. (5)Expected dividend is assumed to be 0% as ACM has no history or expectation of paying a dividend on its common stock. Non-employee Awards The following table summarizes the Company’s non-employee share option activities during the three months ended March 31, 2024: Number of Option Shares Weighted Average Grant Date Fair Value Weighted Average Exercise Price Weighted Average Remaining Contractual Term Outstanding at December 31, 2023 1,170,795 $ 0.42  $ 1.31  2.66 years Exercised (98,651) 0.22 0.50  Forfeited/cancelled (1,903) 0.22 0.50  Outstanding at March 31, 2024 1,070,241 $ 0.44  $ 1.39  2.51 years Vested and exercisable at March 31, 2024 1,070,241 As of March 31, 2024 and December 31, 2023, $0 and $9, respectively, of total unrecognized non-employee stock-based compensation expense, net of estimated forfeitures, related to stock-based awards were expected to be recognized over a weighted-average period of 0 years and 0.2 years, respectively. Total recognized compensation cost may be adjusted for future changes in estimated forfeitures. The aggregate intrinsic value of options exercised in the three months ended March 31, 2024 was $2,756. The aggregate intrinsic value of options outstanding and exercisable as of March 31, 2024 was $29,702. ACM Shanghai 2019 Option Grants In January 2020, ACM Shanghai adopted a 2019 Stock Option Incentive Plan (the “2019 Subsidiary Stock Option Plan”) that provides for, among other incentives, the granting to officers, directors, and employees of options to purchase shares of ACM Shanghai’s common stock. The following table summarizes the stock option activities of the ACM Shanghai 2019 Subsidiary Stock Option Plan during the three months ended March 31, 2024: Number of Option Shares in ACM Shanghai  Weighted Average Grant Date Fair Value Weighted Average Exercise Price Weighted Average  Remaining Contractual Term Outstanding at December 31, 2023 3,134,883 $ 0.24  $ 1.85  0.85 years Forfeited/cancelled (92,308) $ 0.24  $ 1.85  Outstanding at March 31, 2024 3,042,575 $ 0.24  $ 1.85  0.65 years Vested and exercisable at March 31, 2024 3,042,575 The aggregate intrinsic value of options exercised in the three months ended March 31, 2024 was $0. The aggregate intrinsic value of options outstanding and exercisable as of March 31, 2024 was $31,616. ACM Shanghai 2023 Option Grants In June 2023, ACM Shanghai adopted a 2023 Stock Option Incentive Plan (the "2023 Subsidiary Stock Option Plan”) that provides for, among other incentives, the granting to officers, directors, and employees of options to purchase shares of ACM Shanghai’s common stock. The vesting conditions consist of service periods conditions and performance conditions related to certain sales and research and development progress targets determined by the Board of Directors of ACM Shanghai. The following table summarizes the ACM Shanghai 2023 Subsidiary Stock Option Plan’s stock option activities during the three months ended March 31, 2024: Number of Option Shares in ACM Shanghai  Weighted Average Grant Date Fair Value Weighted Average Exercise Price Weighted Average  Remaining Contractual Term Outstanding at December 31, 2023 10,575,500 $ 9.49  $ 7.06  3.09 years Forfeited/cancelled (84,000) $ 9.49  $ 7.06  Outstanding at March 31, 2024 10,491,500 $ 9.12  $ 7.01  2.84 years Vested and exercisable at March 31, 2024 - During the three months ended March 31, 2024, ACM Shanghai did not grant any options from the 2023 Subsidiary Stock Option Plan. As of March 31, 2024 and December 31, 2023, $65,682 and $79,882, respectively, of total unrecognized non-employee stock-based compensation expense, net of estimated forfeitures, related to ACM Shanghai stock-based awards were expected to be recognized over a weighted-average period of 1.8 years and 2.1 years, respectively. Total recognized compensation cost may be adjusted for future changes in estimated forfeitures. The aggregate intrinsic value of options exercised in the three months ended March 31, 2024 was $0. The aggregate intrinsic value of options outstanding and exercisable as of March 31, 2024 were $54,686 and $0, respectively. The following table summarizes the components of stock-based compensation expense included in the condensed consolidated statements of comprehensive income: Three Months Ended March 31, 2024 2023 Stock-Based Compensation Expense: Cost of revenue $ 781  $ 125  Sales and marketing expense 3,027  431  Research and development expense 4,503  701  General and administrative expense 6,258  811  $ 14,569  $ 2,068  Three Months Ended March 31, 2024 2023 Stock-based compensation expense by type: Employee stock purchase plan $ 2,353  $ 2,018  Non-employee stock purchase plan 9  11  2019 and 2023 Subsidiary option grants 12,207  39  $ 14,569  $ 2,068

v3.24.1.u1

INCOME TAXES	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carry-forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period during which such rates are enacted. The Company considers all available evidence to determine whether it is more likely than not that some portion or all of the deferred tax assets will be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become realizable. Management considers the scheduled reversal of deferred tax liabilities (including the impact of available carryback and carry-forward periods) and projected taxable income in assessing the realizability of deferred tax assets. In making such judgments, significant weight is given to evidence that can be objectively verified. As of each reporting date, management considers new evidence, both positive and negative, that could affect its view of the future realization of deferred tax assets. Prior to September 30, 2019, the Company had recorded a valuation allowance for the full amount of net deferred tax assets in the United States, as the realization of deferred tax assets was uncertain. Since September 30, 2019, the Company has not maintained a valuation allowance except for a partial valuation allowance on certain U.S. and foreign deferred tax assets. In order to recognize the remaining U.S. deferred tax assets that continue to be subject to a valuation allowance, the Company will need to generate sufficient U.S. taxable income in future periods before the expiration of the deferred tax assets governed by the tax code. ACM Shanghai has shown a three-year historical cumulative profit and has projections of future income. As a result, the Company does not maintain a valuation allowance. The Company accounts for uncertain tax positions in accordance with the authoritative guidance on income taxes under which the Company may only recognize or continue to recognize tax positions that meet a more likely than not threshold. The Company recognizes accrued interest and penalties related to unrecognized tax benefits as a component of the provision for income taxes. The Company’s effective tax rate differs from statutory rates of 21% for U.S. federal income tax purposes and 15% to 25% for Chinese income tax purposes due to the effects of the valuation allowance and certain permanent differences from book-tax differences, including stock based compensation, deemed dividend income under Subchapter F of the U.S. Internal Revenue Code of 1986, as amended (Subpart F), and global intangible low-taxed income (GILTI) inclusions, and R&D super deduction. As a result, the Company recorded income tax expense of $4,369 and $2,879 during the three months ended March 31, 2024 and 2023, respectively. The decrease in the Company's effective income tax rate for the three months ended March 31, 2024 compared to the same period of the prior year was primarily due to an increased benefit from certain permanent deductions in a foreign jurisdiction. Under the change in Section 174 made by the Tax Cuts and Jobs Act of 2017 which became effective on January 1, 2022, the Company is required to capitalize, and subsequently amortize R&D expenses over fifteen years for research activities conducted outside of the U.S. The capitalization of overseas R&D expenses results in a significant increase in the Company’s global intangible low-taxed income inclusion. The Company had total unrecognized tax benefits of $13,026 as of both March 31, 2024 and December 31, 2023. If recognized, the net impact to effective rate, after indirect offset, would be $12,943. The Company did not expect any reversal of unrecognized tax benefits in the next 12 months. The Company will recognize interest and penalties, when they occur, related to uncertain tax provisions as a component of tax expense. For the three months ended March 31, 2024 and 2023, $338 and $284 of interest and penalties was recognized, respectively. The Company is subject to taxation in the United States, state, and foreign jurisdictions. All tax returns will remain open for examination by the federal and state authorities for three and four years, respectively, from the date of utilization of any net operating loss or credits. Certain tax years are subject to foreign income tax examinations by tax authorities until the statute of limitations expire. The Company’s four principal mainland China subsidiaries, ACM Shanghai, ACM Wuxi, ACM Beijing and ACM Lingang, are liable for mainland China corporate income taxes at the rates of 15%, 25%, 25% and 15%, respectively. Pursuant to the Corporate Income Tax Law of mainland China, ACM’s mainland China subsidiaries generally would be liable for mainland China corporate income taxes as a rate of 25%. According to Guoshuihan 2009 No. 203, an entity certified as an “advanced and new technology enterprise” is entitled to a preferential income tax rate of 15%. ACM Shanghai was certified as an “advanced and new technology enterprise” in 2012 and again in 2016, 2018, and 2021, with an effective period of three years and is expected to be re-certified for future years in 2024. In 2022, ACM Shanghai was certified as an eligible integrated circuit production enterprise and was entitled to a preferential income tax rate of 12.5% from January 1, 2020 to December 31, 2022. Certain entities which meet requirements according to the Policy of the Lingang New area in China (Shanghai) Pilot Free Trade Zone are entitled to a preferential income tax rate of 15%. ACM Lingang was certified for this in 2021, and this preferential income tax rate is valid from January 1, 2020 until December 31, 2024. Income tax expense was as follows: Three Months Ended March 31, 2024 2023 Total income tax expense $ (4,369) $ (2,879)

v3.24.1.u1

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES The Company leases offices under non-cancelable operating lease agreements. See Note 11 for future minimum lease payments under non-cancelable operating lease agreements with initial terms of one year or more. As of March 31, 2024, the Company had $24,285 of open capital commitments to construction contracts and had additional $1,409 of capital investment commitments. As of December 31, 2023, the Company had $30,936 of open commitments to construction contracts and had additional $7,413 of capital investment commitments. Covenants in ACM Lingang’s Grant Contract for State-owned Construction Land Use Right in Shanghai City (Category of R&D Headquarters and Industrial Projects) with the China (Shanghai) Pilot Free Trade Zone Lingang Special Area Administration require, among other things, that ACM Lingang pay liquidated damages in the event that (a) it does not make a total investment (including the costs of construction, fixtures, equipment and grant fees) of at least RMB 450.0 million ($62,600) or (b) within six years after the land use right is obtained, the Company does not (i) generate a minimum specified amount of annual sales of products manufactured on the granted land or (ii) pay to mainland China at least RMB 157.6 million ($22,000) in annual total taxes (including value-added taxes, corporate income tax, personal income taxes, urban maintenance and construction taxes, education surcharges, stamp taxes, and vehicle and shipping taxes) as a result of operations in connection with the granted land. As of March 31, 2024 and December 31, 2023, the Company had paid in total $132,014 and $116,932, respectively for its Lingang-related investments. The Construction Completion Milestone was required to be met by January 9, 2024 but was not achieved. However, ACM Lingang believes it will receive the refund without penalty based on its explanation to the respective regulatory authorities of logistics-related delays, and expects that it will meet the milestone before July 9, 2024. The Company cannot guarantee that ACM Lingang will achieve the missed milestone in 2024, or even if it does achieve the milestone in 2024, that it will be refunded some or all of the 20% portion of the performance deposit of RMB 2.5 million ($0.4 million). In the normal course of business, the Company is subject to contingencies, including legal proceedings and environmental claims arising out of the normal course of businesses that relate to a wide range of matters, including among others, contracts breach liability. The Company records accruals for such contingencies based upon the assessment of the probability of occurrence and, where determinable, an estimate of the liability. Management may consider many factors in making these assessments including past history, scientific evidence and the specifics of each matter. Some of these contingencies involve claims that are subject to substantial uncertainties and un-estimable damages. The Company’s management has evaluated all such proceedings and claims that existed as of March 31, 2024 and December 31, 2023. In the opinion of management, no provision for liability nor disclosure was required as of March 31, 2024 related to any claim against the Company because: (a) there is not a reasonable possibility that a loss exceeding amounts already recognized (if any) may be incurred with respect to such claim; (b) a reasonably possible loss or range of loss cannot be estimated; or (c) such estimate is immaterial. As of March 31, 2024, the Company had no outstanding legal proceedings.

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SEGMENT INFORMATION	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
SEGMENT INFORMATION	SEGMENT INFORMATION The Company identifies operating segments according to how the business activities are managed and evaluated. The Company’s chief operating decision maker (“CODM”) has been identified as ACM’s Chief Executive Officer. The Company's operating segments include ACM Research and ACM Shanghai. As the Company is engaged in the developing, manufacture and sale of capital equipment to global semiconductor manufacturers, and each of the operating segments share similar economic and other qualitative characteristics, the results of the Company’s operating segments are aggregated into one reportable segment. For geographical reporting, revenue by geographic location is determined by the location of customers’ facilities to which products were shipped. Long-lived assets consist primarily of property, plant and equipment, land use right, and right-of-use assets and are attributed to the geographic location in which they are located. Long-lived assets by geographic region as of the periods ended were as follows: March 31, 2024 December 31, 2023 Long-lived assets by geography:    Mainland China $ 231,208  $ 209,725     Korea 11,630  12,190     United States 1,259  1,276  Total $ 244,097  $ 223,191

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STATUTORY SURPLUS RESERVE	3 Months Ended
	Mar. 31, 2024
STATUTORY SURPLUS RESERVE [Abstract]
STATUTORY SURPLUS RESERVE	STATUTORY SURPLUS RESERVE In accordance with mainland China’s Foreign Enterprise Law, ACM Shanghai, ACM Lingang, and ACM Wuxi are required to make appropriation to reserve funds, comprising the statutory surplus reserve and discretionary surplus reserve, based on after-tax net income in accordance with generally accepted accounting principles of mainland China (“mainland China GAAP”). Appropriations to the statutory surplus reserve are required to be at least 10% of the after-tax net income determined in accordance with mainland China GAAP until the reserve is equal to 50% of the entities’ registered capital. The amount is calculated annually at the end of each calendar year. The balances of statutory reserve funds was $30,060 as of both March 31, 2024 and December 31, 2023, and is presented as statutory surplus reserve on the Company’s condensed consolidated balance sheets.

v3.24.1.u1

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss) Attributable to Parent	$ 17,433	$ 7,145

v3.24.1.u1

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024 shares
Trading Arrangements, by Individual
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Jian Wang [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On March 7, 2024, Jian Wang, Chief Executive Officer and President of ACM Shanghai, adopted a Rule 10b5-1 trading arrangement (the “Wang Plan”) that is intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act. The Wang Plan allows for the contemporaneous exercise of options and sale of up to 120,000 shares of Class A common stock, at specific market prices, commencing on June 6, 2024, and continuing until (i) all such options are exercised and the underlying shares are sold, (ii) December 31, 2024, or (iii) such date that the Wang Plan is otherwise terminated according to its terms, whichever comes first.
Name	Jian Wang
Title	Chief Executive Officer and President of ACM Shanghai,
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 7, 2024
Arrangement Duration	299 days
Aggregate Available	120,000
Mark McKechnie [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On March 7, 2024, Mark McKechnie, Chief Financial Officer of ACM Research, adopted a Rule 10b5-1 trading arrangement (the “McKechnie Plan”) that is intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act. The McKechnie Plan allows for the contemporaneous exercise of options and sale of up to 81,516 shares of Class A common stock, at specific market prices, commencing on June 6, 2024, and continuing until (i) all such options are exercised and the underlying shares are sold, (ii) December 31, 2025, or (iii) such date that the McKechnie Plan is otherwise terminated according to its terms, whichever comes first.
Name	Mark McKechnie
Title	Chief Financial Officer of ACM Research,
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 7, 2024
Arrangement Duration	664 days
Aggregate Available	81,516
Lisa Feng [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On March 14, 2024, Lisa Feng, Chief Financial Officer of ACM Shanghai, adopted a Rule 10b5-1 trading arrangement (the “Feng Plan”) that is intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act. The Feng Plan allows for the contemporaneous exercise of options and sale of up to 30,000 shares of Class A common stock, at specific market prices, commencing on June 13, 2024, and continuing until (i) all such options are exercised and the underlying shares are sold, (ii) June 4, 2025, or (iii) such date that the Feng Plan is otherwise terminated according to its terms, whichever comes first.
Name	Lisa Feng
Title	Chief Financial Officer of ACM Shanghai
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 14, 2024
Arrangement Duration	447 days
Aggregate Available	30,000

v3.24.1.u1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The Company’s condensed consolidated financial statements include the accounts of ACM and its subsidiaries. ACM’s subsidiaries are those entities in which ACM, directly or indirectly, controls a majority of the voting power. All significant intercompany transactions and balances have been eliminated upon consolidation. The accompanying condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and the rules and regulations of the Securities and Exchange Commission (the “SEC”) for reporting on Form 10-Q. Accordingly, they do not include all the information and footnotes required by GAAP for complete financial statements. The accompanying condensed consolidated financial statements should be read in conjunction with the historical consolidated financial statements of the Company for the year ended December 31, 2023 included in ACM’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023. The accompanying condensed consolidated financial statements are unaudited. In the opinion of management, these unaudited condensed consolidated financial statements of the Company reflect all adjustments that are necessary for a fair presentation of the Company’s financial position and results of operations. Such adjustments are of a normal recurring nature, unless otherwise noted. The balance sheet as of March 31, 2024 and the results of operations for the three months ended March 31, 2024 are not necessarily indicative of the results to be expected for any future period.
Use of Estimates	Use of Estimates The preparation of the condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the balance sheet date and the reported revenues and expenses during the reported period in the condensed consolidated financial statements and accompanying notes. The Company’s significant accounting estimates and assumptions include, but are not limited to, those used for revenue recognition and deferred revenue, the valuation and recognition of fair value of certain short-term investments and long-term investments, stock-based compensation arrangements, realization of deferred tax assets, assessment for impairment of long-lived assets and long-term investments, allowance for credit losses, inventory valuation, useful lives of property, plant and equipment and useful lives of intangible assets. Management evaluates these estimates and assumptions on a regular basis. Actual results could differ from those estimates and assumptions.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of cash on hand, bank deposits that are unrestricted as to withdrawal and use, and highly liquid investments with an original maturity date of three months or less at the date of purchase. At times, cash deposits may exceed government-insured limits. The following table presents cash and cash equivalents, according to jurisdiction as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 United States $ 45,179  $ 43,614  Mainland China 101,590  70,418  China Hong Kong 63,401  64,057  Korea 1,068  3,934  Singapore 67  67  Total $ 211,305  $ 182,090  The amounts in mainland China do not include short-term and long-term time deposits which totaled $76,205 and $121,342 at March 31, 2024 and December 31, 2023, respectively. Cash held in the U.S. exceeds the Federal Deposit Insurance Corporation insurance limits and is subject to risk of loss. No losses have been experienced to date. Cash amounts held in mainland China are subject to a series of risk control regulatory standards from mainland China bank regulatory authorities. ACM’s subsidiaries in mainland China are required to obtain approval from the State Administration of Foreign Exchange (“SAFE”) to transfer funds into or out of mainland China. SAFE requires a valid agreement to approve the transfers, which are processed through a bank. Other than these mainland China foreign exchange restrictions, ACM’s subsidiaries in mainland China are not subject to any restrictions and limitations on its ability to transfer funds to ACM or among our other subsidiaries. However, cash held in mainland China does exceed applicable insurance limits and is subject to risk of loss, although no such losses have been experienced to date. ACM California periodically procures goods and services on behalf of ACM Shanghai. For these transactions, ACM Shanghai makes cash payments to ACM California in accordance with applicable transfer pricing arrangements. For the three months ended March 31, 2024 and 2023, cash payments from ACM Shanghai to ACM California for the procurement of goods and services was $4,648 and $10,931, respectively. ACM California periodically borrows funds for working capital advances from its direct parent, CleanChip. ACM California repays or renews these intercompany loans in accordance with their terms. For sales through CleanChip and ACM Research, a certain amount of sales or advanced payments from customers is repatriated back to ACM Shanghai in accordance with applicable transfer pricing arrangements in the ordinary course of business. ACM Research provides services to certain customers located in the U.S., Europe and other regions outside of mainland China to support the evaluation of first tools and provide support for tools under warranty on behalf of ACM Shanghai. For these transactions, ACM Shanghai makes cash payments to ACM Research in accordance with applicable transfer pricing arrangements. Amounts held in Korea exceed the Korea Deposit Insurance Corporation insurance limits and is subject to risk of loss. No losses have been experienced to date. There is no additional restriction for the transfer of cash from bank accounts in the U.S., Korea, Singapore and Hong Kong. For the three months ended March 31, 2024 and 2023, with the exception of sales and services-related transfer-pricing payments in the ordinary course of business, no transfers, or distributions have been made between ACM Research and its subsidiaries, including ACM Shanghai, or to holders of ACM Research Class A common stock.
Time Deposits	Time Deposits Time deposits are deposited with banks in mainland China with fixed terms and interest rates which cannot be withdrawn before maturity, and are presented as short-term deposits and long-term deposits in the condensed consolidated financial statements based on their expected time of collection. They are also subject to the risk control regulatory standards described above upon maturity.
Financial Instruments	Financial Instruments The Company periodically invests in equity securities, and maintains an investment portfolio of various holdings, types, and maturities. For equity investments that do not have a readily determinable fair value, the Company classified them as long-term investments, and records them using either: 1) the measurement alternative which measures the equity investments at cost minus impairment, if any, plus or minus changes resulting from qualifying observable price changes; or 2) the equity method whereby the Company recognizes its proportional share of the income or loss from the equity method investment. The equity method is utilized when the equity investments are common stock or in substance common stock, and the Company does not have the ability to control the investee but is deemed to have the ability to exercise significant influence over the investee’s operating or financial policies. For equity investments that have a readily determinable fair value, the Company classified them as short-term investments, and records them at fair market value on a recurring basis based upon quoted market prices. Realized and unrealized gains and losses resulting from application of the measurement alternative, the impact of the application of the equity method to the Company’s equity investments, and recognition of changes in fair market value, as applicable, are recognized as non-operating income (expenses), net in the condensed consolidated statements of comprehensive income. The Company defines fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, the Company considers the principal or most advantageous market in which it would transact, and it considers assumptions that market participants would use when pricing the asset or liability. A fair value hierarchy has been established that prioritizes the inputs to valuation techniques used to measure fair value. The level of an asset or liability in the hierarchy is based on the lowest level of input that is significant to the fair value measurement. Assets and liabilities carried at fair value are classified and disclosed in one of the following three categories: Level 1: Valuations based on quoted prices in active markets for identical assets or liabilities with sufficient volume and frequency of transactions. Level 2: Valuations based on observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active for identical assets or liabilities, or model-derived valuations techniques for which all significant inputs are observable in the market or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3: Valuations based on unobservable inputs to the valuation methodology that are significant to the measurement of fair value of assets or liabilities and based on non-binding, broker-provided price quotes and may not have been corroborated by observable market data. The Company’s primary financial instruments include its cash, cash equivalents, short term and long term deposits, restricted cash, short-term and long-term investments, other receivables, accounts receivable, accounts payable, and short-term and long-term borrowings. The estimated fair value of cash and cash equivalents, short-term time deposits, accounts receivable, other receivables, accounts payable, and short-term borrowings approximates their carrying value due to the short period of time to their maturities. All transfers between fair value hierarchy levels are recognized by the Company at the end of each reporting period. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement in its entirety, requires judgment and considers factors specific to the investment. The inputs or methodology used for valuing financial instruments are not necessarily an indication of the risks associated with investment in those instruments. The Company did not have any assets and liabilities measured at fair value on a non-recurring basis as of March 31, 2024, and the Company did not recognize any unrealized gains (upward adjustments) or unrealized losses (downward adjustments) resulting from observable price changes in orderly transactions for an identical or similar investment of the same issuer for its long-term investments accounted for using measurement alternatives during the three months ended March 31, 2024 and 2023.
Basic and Diluted Net Income per Share of Common Stock	Basic and diluted net income per share of common stock is presented using the two-class method, which allocates undistributed earnings to common stock and any participating securities according to dividend rights and participation rights on a proportionate basis. Under the two-class method, basic net income per share of common stock is computed by dividing the sum of distributed and undistributed earnings attributable to common stockholders by the weighted average number of shares of common stock outstanding during the period. ACM Research did not have any participating securities outstanding during the three months ended March 31, 2024 and 2023. ACM Research has been authorized to issue Class A and Class B common stock since redomesticating in Delaware in November 2016. The two classes of common stock are substantially identical in all material respects, except for voting rights. Since ACM Research did not declare any cash dividends during the three months ended March 31, 2024 or 2023, the net income per share of common stock attributable to each class is the same under the “two-class” method. As such, the two classes of common stock have been presented on a combined basis in the condensed consolidated statements of comprehensive income and in the above computation of net income per share of common stock. Diluted net income per share of common stock reflects the potential dilution from securities, such as stock options that could share in ACM Research’s earnings. Certain potential dilutive securities were excluded from the net income per share calculation because the impact would be anti-dilutive. The number of potentially dilutive shares that were not included in the calculation of diluted net income per share in the periods presented where their inclusion would be anti-dilutive were 728,575 and 1,967,685 stock options for the three months ended March 31, 2024 and 2023, respectively.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to credit risk consist principally of cash and cash equivalents, time deposits, and accounts receivable. The Company deposits and invests its cash and cash equivalents and time deposits with financial institutions that management believes are creditworthy.
Recently issued accounting pronouncements not yet adopted	Recently issued accounting pronouncements not yet adopted In November 2023, the FASB issued ASU No. 2023-07, Improvements to Reportable Segment Disclosures. This ASU updates reportable segment disclosure requirements by requiring disclosures of significant reportable segment expenses that are regularly provided to the Chief Operating Decision Maker (“CODM”) and included within each reported measure of a segment's profit or loss. This ASU also requires disclosure of the title and position of the individual identified as the CODM and an explanation of how the CODM uses the reported measures of a segment’s profit or loss in assessing segment performance and deciding how to allocate resources. The ASU is effective for annual periods beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Adoption of the ASU should be applied retrospectively to all prior periods presented in the financial statements. Early adoption is also permitted. The Company is currently evaluating the provisions of this ASU and expect to adopt it for the year ending December 31, 2024. In December 2023, the FASB issued ASU No. 2023-09, Improvements to Income Tax Disclosures (Topic 740). The ASU requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as additional information on income taxes paid. The ASU is effective on a prospective basis for annual periods beginning after December 15, 2024. Retrospective application is permitted. Early adoption is also permitted for annual financial statements that have not yet been issued or made available for issuance. The Company is currently evaluating the provisions of this ASU.

v3.24.1.u1

DESCRIPTION OF BUSINESS (Tables)	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Direct or Indirect Interests of Subsidiaries	The Company has direct or indirect interests in the following subsidiaries: Effective interest held as at Name of subsidiaries Place and date of incorporation  Principal Activities March 31, 2024 December 31, 2023 ACM Research (Shanghai), Inc. ("ACM Shanghai") Mainland China, May 2005  Principal operating subsidiary 82.1  % 82.1  % ACM Research (Wuxi), Inc. ("ACM Wuxi") Mainland China, July 2011  Sales and services 82.1  % 82.1  % CleanChip Technologies Limited ("CleanChip") Hong Kong, June 2017  Trading partner between ACM Shanghai and its customers 82.1  % 82.1  % ACM Research Korea CO., LTD. Korea, December 2017  Sales, marketing, R&D, production 82.1  % 82.1  % ACM Research ( Lingang), Inc. ("ACM Lingang") (1) Mainland China, March 2019  Management of production activities 82.1  % 82.1  % ACM Research (CA), Inc. ("ACM California") USA, April 2019  Procurement for ACM Shanghai 82.1  % 82.1  % ACM Research (Cayman), Inc. Cayman Islands, April 2019  Administrative function (inactive) 100.0  % 100.0  % ACM Research (Singapore) PTE. Ltd. ("ACM Singapore") Singapore, August 2021  Sales, marketing, business development 100.0  % 100.0  % ACM Research (Beijing), Inc. ("ACM Beijing") Mainland China, February 2022  Sales, marketing, business development 82.1  % 82.1  % Hanguk ACM CO., LTD Korea, March 2022  Sales, services, business development 100.0  % 100.0  % Yusheng Micro Semiconductor (Shanghai) Co., Ltd. Mainland China, June 2023  Business development 82.1  % 82.1  % ACM-Wooil Microelectronics (Shanghai) Co., Ltd. Mainland China, June 2023  Component development and production 59.4  % 59.4  % (1) ACM Research (Lingang) Inc. is the English name referred to by its Chinese language name Shengwei Research (Shanghai), Inc., or ACM Shengwei in prior filings. ACM Research (Lingang), Inc. and Shengwei Research (Shanghai), Inc. refer to the same entity.

v3.24.1.u1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Cash and Cash Equivalents	The following table presents cash and cash equivalents, according to jurisdiction as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 United States $ 45,179  $ 43,614  Mainland China 101,590  70,418  China Hong Kong 63,401  64,057  Korea 1,068  3,934  Singapore 67  67  Total $ 211,305  $ 182,090
Summary of Time Deposits	At March 31, 2024 and December 31, 2023, time deposits consisted of the following: March 31, 2024 December 31, 2023 Deposit in China Merchant Bank which matured on January 29, 2024 with an annual interest rate of 2.85% $ —  $ 29,797  Deposit in Bank of Ningbo which matured on February 17, 2024 with an annual interest rate of 2.85% $ —  $ 44,630  Deposit in Shanghai Pudong Development Bank which matures on October 20, 2025 with an annual interest rate of 3.10% $ 7,361  $ 7,322  Deposit in Shanghai Pudong Development Bank which matures on November 14, 2025 with an annual interest rate of 3.10% $ 4,407  $ 7,307  Deposit in Shanghai Pudong Development Bank which matures on December 8, 2025 with an annual interest rate of 3.10% $ —  $ 4,376  Deposit in Shanghai Pudong Development Bank which matures on December 15, 2025 with an annual interest rate of 3.10% $ 1,465  $ 4,373  Deposit in Shanghai Pudong Development Bank which matures on December 30, 2025 with an annual interest rate of 3.10% $ —  $ 2,912  Deposit in China Industrial Bank which matures on January 3, 2026 with an annual interest rate of 3.15% $ 14,608  $ 14,528  Deposit in China Everbright Bank which matures on December 5, 2024 with an annual interest rate of 5.38% $ —  $ 3,079  Deposit in China Everbright Bank which matures on May 22, 2024 with an annual interest rate of 5.28% $ 3,057  $ 3,018  Deposit in China Everbright Bank which matured on April 5, 2024 with an annual interest rate of 5.33% $ 3,037  $ —  Deposit in China Merchant Bank, Lujiazui Branch which matures on May 27, 2024 with an annual interest rate of 1.85% $ 14,090  $ —  Deposit in China Merchant Bank, Huaihai Branch which matures on May 27, 2024 with an annual interest rate of 1.85% $ 14,090  $ —  Deposit in Bank of Ningbo which matures on September 11, 2024 with an annual interest rate of 1.50% $ 14,090  $ —  $ 76,205  $ 121,342
Fair Value, by Balance Sheet Grouping	Quoted Prices in Active Markets for Identical Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total As of March 31, 2024: Assets      Cash and cash equivalents $ 36,509  $ —  $ —  $ 36,509       Short-term investments 18,648  —  —  18,648  $ 55,157  $ —  $ —  $ 55,157  As of December 31, 2023: Assets      Cash and cash equivalents $ 37,518  $ —  $ —  $ 37,518       Short-term investments 21,312  —  —  21,312  $ 58,830  $ —  $ —  $ 58,830  Assets and liabilities measured at fair value on a non-recurring basis:  Quoted Prices in Active Markets for Identical Liabilities (Level 1)  Significant Other Observable Inputs (Level 2)  Significant Unobservable Inputs (Level 3)  Total  As of December 31, 2023:  Assets Investments accounted for using measurement alternative $ —  $ —  $ 10,378  $ 10,378  $ —  $ —  $ 10,378  $ 10,378
Basic and Diluted Net Income per Common Share	Basic and diluted net income per share of common stock are calculated as follows: Three Months Ended March 31, 2024 2023 Numerator:        Net income $ 22,092  $ 8,963         Less: Net income attributable to non-controlling interests 4,659  1,818  Net income available to common stockholders, basic $ 17,433  $ 7,145         Less: Dilutive effect arising from stock-based awards by ACM Shanghai 354  93  Net income available to common stockholders, diluted $ 17,079  $ 7,052  Weighted average shares outstanding, basic 61,367,184 59,736,764        Effect of dilutive securities 4,875,137 5,322,013        Weighted average shares outstanding, diluted 66,242,321 65,058,777 Net income per share of common stock: Basic $ 0.28  $ 0.12  Diluted $ 0.26  $ 0.11

v3.24.1.u1

REVENUE FROM CONTRACTS WITH CUSTOMERS (Tables)	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Disaggregated Revenue Information	The Company assesses revenues based upon the nature or type of goods or services it provides and the geographic location of the customer facility. The following tables present disaggregated revenue information: Three Months Ended March 31, 2024 2023 Single Wafer Cleaning, Tahoe and Semi-Critical Cleaning Equipment $ 109,470  $ 36,614  ECP (front-end and packaging), Furnace and Other Technologies 25,800  26,598  Advanced Packaging (excluding ECP), Services & Spares 16,921  11,044  Total Revenue by Product Category $ 152,191  $ 74,256  Three Months Ended March 31, 2024 2023 Mainland China $ 152,135  $ 72,458  Other regions 56  1,798  $ 152,191  $ 74,256
Accounts Receivables and Contract Liabilities	Below are the accounts receivables and contract liabilities balances as of: March 31, 2024 December 31, 2023       Accounts receivable 296,371  283,186        Advances from customers 182,547  181,368         Deferred revenue 4,405  3,687  Below are revenues recognized from amounts included in contract liabilities at the beginning of the year: Three Months Ended March 31, 2024 2023 Revenue recognized from amounts included in contract liabilities at the beginning of the year $ 29,188  $ 15,212

v3.24.1.u1

ACCOUNTS RECEIVABLE (Tables)	3 Months Ended
	Mar. 31, 2024
Receivables [Abstract]
Accounts Receivable	At March 31, 2024 and December 31, 2023, accounts receivable consisted of the following: March 31, 2024 December 31, 2023 Accounts receivable $ 302,372  $ 288,016  Less: Allowance for credit losses (6,001) (4,830) $ 296,371  $ 283,186  The movement of the allowance for credit losses for the three months ended March 31, 2024 is as follows: Allowance for credit losses, before tax, as of January 1 Provision for credit losses Allowance for credit losses, before tax, as of March 31 March 31, 2024 $ (4,830) (1,171) $ (6,001)

v3.24.1.u1

INVENTORIES (Tables)	3 Months Ended
	Mar. 31, 2024
Inventory Disclosure [Abstract]
Inventories	At March 31, 2024 and December 31, 2023, inventories consisted of the following: March 31, 2024 December 31, 2023 Raw materials $ 256,332  $ 235,062  Work-in-process 61,871  81,438  Finished goods 262,937  228,895  Total inventory $ 581,140  $ 545,395

v3.24.1.u1

PROPERTY, PLANT AND EQUIPMENT, NET (Tables)	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	At March 31, 2024 and December 31, 2023, property, plant and equipment consisted of the following: March 31, 2024 December 31, 2023 Buildings and plants $ 82,933  $ 83,109  Manufacturing equipment 16,702  16,556  Office equipment 5,061  4,953  Transportation equipment 402  404  Leasehold improvement 7,961  7,889  Total cost 113,059  112,911  Less: Total accumulated depreciation and amortization (19,531) (17,503) Construction in progress 125,294  106,440  Total property, plant and equipment, net $ 218,822  $ 201,848

v3.24.1.u1

LAND USE RIGHT, NET (Tables)	3 Months Ended
	Mar. 31, 2024
Land Use Right, Net [Abstract]
Land Use Rights	A summary of land use right is as follows: March 31, 2024 December 31, 2023 Land use right purchase amount $ 8,977  $ 8,996  Less: accumulated amortization (672) (629) Land use right, net $ 8,305  $ 8,367
Annual Amortization of Land Use Right	The annual amortization of land use right is as follows: Year ending December 31, remainder of 2024 $ 135  2025 180  2026 180  2027 180  2028 180  2029 and thereafter 7,450  Total $ 8,305

v3.24.1.u1

OTHER LONG-TERM ASSETS (Tables)	3 Months Ended
	Mar. 31, 2024
Other Assets, Noncurrent Disclosure [Abstract]
Other Long-term Assets	At March 31, 2024 and December 31, 2023, other long-term assets consisted of the following: March 31, 2024 December 31, 2023 Prepayments for property, plant and equipment $ 7,690  $ 3,380  Lease deposits 867  834  Security deposit for land use right 695  696  Others 1,219  1,140  Total other long-term assets $ 10,471  $ 6,050

v3.24.1.u1

SHORT-TERM BORROWINGS (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Short-Term Borrowings	At March 31, 2024 and December 31, 2023, short-term borrowings consisted of the following: March 31, 2024 December 31, 2023 Line of credit up to RMB 150,000 from China Everbright Bank, 1)due on August 29, 2024 with an annual interest rate of 3.00%. 2,459  2,463  Line of credit up to RMB 40,000 from Bank of China, 1)due on September 7, 2024 with an annual interest rate of 2.87%. 5,640  5,648  Line of credit up to RMB 200,000 from China Merchants Bank, 1)due on August 7, 2024 with an annual interest rate of 3.00%. 1,269  1,271  2)due on August 8, 2024 with an annual interest rate of 3.00%. 1,269  1,271  3)due on August 9, 2024 with an annual interest rate of 3.00%. 1,269  1,271  4)due on August 14, 2024 with an annual interest rate of 3.00%. 1,269  1,271  5)due on August 17, 2024 with an annual interest rate of 3.00%. 1,269  1,271  6)due on August 20, 2024 with an annual interest rate of 3.00%. 1,269  1,271  7)due on August 21, 2024 with an annual interest rate of 3.00%. 1,269  1,271  8)due on August 22, 2024 with an annual interest rate of 3.00%. 1,269  1,271  9)due on August 24, 2024 with an annual interest rate of 3.00%. 1,269  1,271  10)due on August 27, 2024 with an annual interest rate of 3.00%. 1,269  1,271  11)due on August 29, 2024 with an annual interest rate of 3.00%. 1,269  1,271  12)due on August 30, 2024 with an annual interest rate of 3.00%. 1,269  1,271  13)due on September 3, 2024 with an annual interest rate of 3.00%. 1,269  1,271  14)due on September 5, 2024 with an annual interest rate of 3.00%. 1,269  1,270  15)due on September 6, 2024 with an annual interest rate of 3.00%. 1,269  1,270  16)due on September 10, 2024 with an annual interest rate of 3.00%. 1,269  1,270  17)due on September 12, 2024 with an annual interest rate of 3.00%. 1,269  1,270  18)due on February 27, 2025 with an annual interest rate of 2.60%. 1,340  —  19)due on February 28, 2025 with an annual interest rate of 2.60%. 1,340  —  20)due on March 1, 2025 with an annual interest rate of 2.60%. 1,340  —  21)due on March 5, 2025 with an annual interest rate of 2.60%. 1,340  —  22)due on March 8, 2025 with an annual interest rate of 2.60%. 1,270  —  Line of credit up to RMB 120,000 from Bank of China, 1)due on March 20, 2025 with an annual interest rate of 2.75%. 16,921  —  Line of credit up to KRW 500,000 from Industrial Bank of Korea, 1)due on July 12, 2024 with an annual interest rate of 6.03%. —  77  Line of credit up to KRW 2,000,000 from Industrial Bank of Korea, 1)due on December 15, 2024 with an annual interest rate of 4.27%. 1,483  1,544  Total $ 54,706  $ 31,335

v3.24.1.u1

OTHER PAYABLES AND ACCRUED EXPENSES (Tables)	3 Months Ended
	Mar. 31, 2024
Payables and Accruals [Abstract]
Other Payables and Accrued Expenses	At March 31, 2024 and December 31, 2023, other payables and accrued expenses consisted of the following: March 31, 2024 December 31, 2023 Accrued commissions $ 15,932  $ 15,572  Accrued warranty 11,339  9,834  Accrued payroll 16,550  14,840  Accrued professional fees 113  696  Accrued machine testing fees 1,863  1,762  Accrued machine sales fees 4,942  6,010  Accrued Lingang construction fees 33,546  33,729  Others 22,813  20,508  Total $ 107,098  $ 102,951

v3.24.1.u1

LEASES (Tables)	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Components of Lease Expense	The components of lease expense were as follows: Three Months Ended March 31, 2024 2023 Operating lease cost $ 973  $ 488  Short-term lease cost 321  282  Total lease cost $ 1,294  $ 770
Supplemental Cash Flow Information Related to Operating Leases	Supplemental cash flow information related to operating leases was as follows: Three Months Ended March 31, 2024 2023      Operating cash outflow from operating leases $ 973  $ 488      Operating lease right-of-use assets obtained in exchange for new operating lease liabilities $ 80  $ 6,592
Maturities of Outstanding Lease Liabilities for Operating Leases	As of March 31, 2024, maturities of outstanding lease liabilities for all operating leases were as follows: December 31, remainder of 2024 $ 2,370  2025 1,800  2026 1,215  2027 1,148  2028 and thereafter 595  Total lease payments $ 7,128  Less: Interest (630) Present value of lease liabilities $ 6,498
Weighted Average Remaining Lease Terms and Discount Rates for Operating Leases	The weighted average remaining lease terms and discount rates for all operating leases were as follows: March 31, 2024 December 31, 2023 Remaining lease term and discount rate: Weighted average remaining lease term (years) 3.37 3.44 Weighted average discount rate 3.87  % 3.91  %

v3.24.1.u1

LONG-TERM BORROWINGS (Tables)	3 Months Ended
	Mar. 31, 2024
Long-Term Debt, by Current and Noncurrent [Abstract]
Long-Term Borrowings	At March 31, 2024 and December 31, 2023, long-term borrowings consisted of the following: March 31, 2024 December 31, 2023 Loan from China Merchants Bank $ 12,919  $ 13,362  Loans from Bank of China 4,759  5,013  Loan from Bank of Shanghai 14,101  14,120  Loan from China CITIC Bank 28,178  28,240  Less: Current portion (6,549) (6,783) Total $ 53,408  $ 53,952
Principal Payments for Outstanding Long-Term Loan	Scheduled principal payments for the outstanding long-term loan, including the current portion, as of March 31, 2024 are as follows: Year ending December 31 remainder of 2024 $ 6,120  2025 43,993  2026 1,851  2027 1,925  2028 2,003  Thereafter 4,065  $ 59,957

v3.24.1.u1

OTHER LONG-TERM LIABILITIES (Tables)	3 Months Ended
	Mar. 31, 2024
Other Liabilities Disclosure [Abstract]
Other Long-Term Liabilities	Other long-term liabilities represent government subsidies received from mainland China governmental authorities for development and commercialization of certain technology but not yet recognized. At March 31, 2024 and December 31, 2023, other long-term liabilities consisted of the following unearned government subsidies: March 31, 2024 December 31, 2023 Subsidies to Stress Free Polishing project, commenced in 2008 and 2017 $ 189  $ 475  Subsidies to other cleaning tools, commenced in 2020 647  632  Subsidies to SW Lingang R&D development in 2021 3,454  3,467  Other 1,179  1,299  Total $ 5,469  $ 5,873

v3.24.1.u1

LONG-TERM INVESTMENT (Tables)	3 Months Ended
	Mar. 31, 2024
Long-Term Investments [Abstract]
Long-Term Investment	Equity investee: Initial investment dates Investment entity Percent ownership by ACM and subsidiaries Investment purchase price Ninebell Co., Ltd. ("Ninebell") September 2017 ACM 20.0% $ 1,200  Shengyi Semiconductor Technology Co., Ltd. ("Shengyi") June 2019 ACM Shanghai 14.0% $ 109  Hefei Shixi Chanheng Integrated Circuit Industry Venture Capital FundPartnership (LP) (“Hefei Shixi”) September 2019 ACM Shanghai 10.0% RMB 30,000 ($4,200) Wooil Flucon Co. ("Wooil") August 2022 ACM Singapore 20.0% $ 1,000  Company D February 2024 ACM Shanghai 16.7% RMB 30,000 ($4,230) Investments accounted for using measurement alternative: Waferworks (Shanghai) Co., Ltd. (“Waferworks”) October 2021 ACM Shanghai 0.3% $ 1,568  Company A September 2023 ACM Shanghai 4.4% RMB 30,000 ($4,200) Shengyi September 2023 ACM Shanghai 1.0% RMB 6,100 ($860) Company B November 2023 ACM Shanghai 1.4% RMB 6,600 ($930) Company C February 2024 ACM Shanghai 5.0% RMB 12,500 ($1,760) Equity investee: March 31, 2024 December 31, 2023 Ninebell $ 5,481  $ 5,632  Wooil 989  1,003  Shengyi 1,999  1,693  Hefei Shixi 7,888  9,174  Company D 4,227  —  Subtotal 20,584  17,502  Investments accounted for using measurement alternative: Waferworks —  1,412  Shengyi 856  857  Company A 4,227  4,236  Company B 930  932  Company C 1,761  —  Other 2,935  2,941  Total 31,293  27,880

v3.24.1.u1

SHORT-TERM INVESTMENTS (Tables)	3 Months Ended
	Mar. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Components of Trading Securities	At March 31, 2024 and December 31, 2023, the components of short-term investments were as follows: March 31, 2024 December 31, 2023 Short-term investments listed in Shanghai Stock Exchange   Cost $ 21,135  $ 20,155    Market value 18,648  21,312
Unrealized Gain (Loss) on Trading Securities	For the three months ended March 31, 2024 and 2023, the net gains (losses) recognized on equity securities were as follows: Three Months Ended March 31, 2024 2023 Unrealized losses recognized during the reporting period on equity securities still held at March 31 $ (2,595) $ (654) Net gains recognized during the period on equity securities sold during the period $ 273  $ 3,994  Total net gains (losses) recognized at March 31 on equity securities $ (2,322) $ 3,340

v3.24.1.u1

RELATED PARTY BALANCES AND TRANSACTIONS (Tables)	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
Related Party Balances and Transactions	The following tables reflect related party transactions in our condensed consolidated financial statements: Advances to related party March 31, 2024 December 31, 2023 Ninebell $ 1,338  $ 2,432  Accounts payable March 31, 2024 December 31, 2023 Ninebell $ 12,571  $ 7,624  Shengyi 3,672  3,783  Total $ 16,243  $ 11,407  Three Months Ended March 31, Purchase of materials 2024 2023 Ninebell $ 14,152  $ 16,397  Shengyi 992  1,973  Total $ 15,144  $ 18,370  Three Months Ended March 31, Service fee charged by 2024 2023 Shengyi $ 73  $ 278

v3.24.1.u1

STOCK-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Summary of Share Option Activities	The following table summarizes the Company’s employee share option activities during the three months ended March 31, 2024: Number of  Option Shares Weighted  Average Grant Date Fair Value Weighted Average Exercise Price Weighted Average Remaining Contractual Term Outstanding at December 31, 2023 9,998,637 $ 5.15  $ 9.59  6.17 years Granted 3,000 23.95 31.92  Exercised (851,954) 2.7 5.74  Forfeited/cancelled (24,330) 11.14 23.08  Outstanding at March 31, 2024 9,125,353 $ 5.37  $ 9.79  6.07 years Vested and exercisable at March 31, 2024 5,278,784 The following table summarizes the Company’s non-employee share option activities during the three months ended March 31, 2024: Number of Option Shares Weighted Average Grant Date Fair Value Weighted Average Exercise Price Weighted Average Remaining Contractual Term Outstanding at December 31, 2023 1,170,795 $ 0.42  $ 1.31  2.66 years Exercised (98,651) 0.22 0.50  Forfeited/cancelled (1,903) 0.22 0.50  Outstanding at March 31, 2024 1,070,241 $ 0.44  $ 1.39  2.51 years Vested and exercisable at March 31, 2024 1,070,241 The following table summarizes the stock option activities of the ACM Shanghai 2019 Subsidiary Stock Option Plan during the three months ended March 31, 2024: Number of Option Shares in ACM Shanghai  Weighted Average Grant Date Fair Value Weighted Average Exercise Price Weighted Average  Remaining Contractual Term Outstanding at December 31, 2023 3,134,883 $ 0.24  $ 1.85  0.85 years Forfeited/cancelled (92,308) $ 0.24  $ 1.85  Outstanding at March 31, 2024 3,042,575 $ 0.24  $ 1.85  0.65 years Vested and exercisable at March 31, 2024 3,042,575 The following table summarizes the ACM Shanghai 2023 Subsidiary Stock Option Plan’s stock option activities during the three months ended March 31, 2024: Number of Option Shares in ACM Shanghai  Weighted Average Grant Date Fair Value Weighted Average Exercise Price Weighted Average  Remaining Contractual Term Outstanding at December 31, 2023 10,575,500 $ 9.49  $ 7.06  3.09 years Forfeited/cancelled (84,000) $ 9.49  $ 7.06  Outstanding at March 31, 2024 10,491,500 $ 9.12  $ 7.01  2.84 years Vested and exercisable at March 31, 2024 -
Assumptions Used to Determine Fair Value of Options Granted	The fair value of options granted to employees is estimated on the grant date using the Black-Scholes valuation with following assumptions: Three Months Ended March 31, 2024 Fair value of common share(1) 31.92 Expected term in years(2) 6.25 Volatility(3) 85.48% Risk-free interest rate(4) 4.23% Expected dividend (5) —% (1)Fair value of Class A common stock value was closing market price of the Class A common stock on the grant date. (2)Expected term of share options is based on the average of the vesting period and the contractual term for each grant. (3)Volatility is calculated based on the historical volatility of ACM in the period equal to the expected term of each grant. (4)Risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected term of the share options in effect at the time of grant. (5)Expected dividend is assumed to be 0% as ACM has no history or expectation of paying a dividend on its common stock.
Summary of Components of Stock-based Compensation Expense	The following table summarizes the components of stock-based compensation expense included in the condensed consolidated statements of comprehensive income: Three Months Ended March 31, 2024 2023 Stock-Based Compensation Expense: Cost of revenue $ 781  $ 125  Sales and marketing expense 3,027  431  Research and development expense 4,503  701  General and administrative expense 6,258  811  $ 14,569  $ 2,068  Three Months Ended March 31, 2024 2023 Stock-based compensation expense by type: Employee stock purchase plan $ 2,353  $ 2,018  Non-employee stock purchase plan 9  11  2019 and 2023 Subsidiary option grants 12,207  39  $ 14,569  $ 2,068

v3.24.1.u1

INCOME TAXES (Tables)	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income Tax Benefit (Expense)	Income tax expense was as follows: Three Months Ended March 31, 2024 2023 Total income tax expense $ (4,369) $ (2,879)

v3.24.1.u1

SEGMENT INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Long-Lived Assets by Geography	March 31, 2024 December 31, 2023 Long-lived assets by geography:    Mainland China $ 231,208  $ 209,725     Korea 11,630  12,190     United States 1,259  1,276  Total $ 244,097  $ 223,191

v3.24.1.u1

DESCRIPTION OF BUSINESS (Details) $ in Thousands		1 Months Ended	3 Months Ended
	Nov. 30, 2021 USD ($) shares	May 31, 2023 shares	Mar. 31, 2024 shares	Dec. 31, 2023	Nov. 30, 2021 ¥ / shares shares
Employee Share Option
Description of Business [Abstract]
Exercise of stock options (in shares)			851,954
ACM Research (Shanghai), Inc. ("ACM Shanghai")
Description of Business [Abstract]
Percentage of ownership after transaction		82.10%
Place and date of incorporation			Mainland China, May 2005
Effective interest held as at			82.10%	82.10%
ACM Research (Shanghai), Inc. ("ACM Shanghai") | Employee Share Option
Description of Business [Abstract]
Exercise of stock options (in shares)		2,150,309
ACM Research (Shanghai), Inc. ("ACM Shanghai") | IPO
Description of Business [Abstract]
Offering of shares (in shares)	43,355,753
Percentage amount of shares offered from shares outstanding					10.00%
Common stock outstanding (in shares)					433,557,100
Share price (in RMB per share) | ¥ / shares					¥ 85.00
Proceeds from issuance initial public offering | $	$ 545,512
Percentage of ownership after transaction	82.50%
ACM Research (Wuxi), Inc. ("ACM Wuxi")
Description of Business [Abstract]
Place and date of incorporation			Mainland China, July 2011
Effective interest held as at			82.10%	82.10%
CleanChip Technologies Limited ("CleanChip")
Description of Business [Abstract]
Place and date of incorporation			Hong Kong, June 2017
Effective interest held as at			82.10%	82.10%
ACM Research Korea CO., LTD.
Description of Business [Abstract]
Place and date of incorporation			Korea, December 2017
Effective interest held as at			82.10%	82.10%
ACM Research ( Lingang), Inc. ("ACM Lingang") (1)
Description of Business [Abstract]
Place and date of incorporation			Mainland China, March 2019
Effective interest held as at			82.10%	82.10%
ACM Research (CA), Inc. ("ACM California")
Description of Business [Abstract]
Place and date of incorporation			USA, April 2019
Effective interest held as at			82.10%	82.10%
ACM Research (Cayman), Inc.
Description of Business [Abstract]
Place and date of incorporation			Cayman Islands, April 2019
Effective interest held as at			100.00%	100.00%
ACM Research (Singapore) PTE. Ltd. ("ACM Singapore")
Description of Business [Abstract]
Place and date of incorporation			Singapore, August 2021
Effective interest held as at			100.00%	100.00%
ACM Research (Beijing), Inc. ("ACM Beijing")
Description of Business [Abstract]
Place and date of incorporation			Mainland China, February 2022
Effective interest held as at			82.10%	82.10%
Hanguk ACM CO., LTD
Description of Business [Abstract]
Place and date of incorporation			Korea, March 2022
Effective interest held as at			100.00%	100.00%
Yusheng Micro Semiconductor (Shanghai) Co., Ltd.
Description of Business [Abstract]
Place and date of incorporation			Mainland China, June 2023
Effective interest held as at			82.10%	82.10%
ACM-Wooil Microelectronics (Shanghai) Co., Ltd.
Description of Business [Abstract]
Place and date of incorporation			Mainland China, June 2023
Effective interest held as at			59.40%	59.40%

v3.24.1.u1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash, cash equivalents and restricted cash and time deposits	$ 211,305		$ 182,090
Short-term and long-term time deposits	76,205		121,342
ACM Shanghai
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash payments for procurement of goods and services	4,648	$ 10,931
United States
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash, cash equivalents and restricted cash and time deposits	45,179		43,614
Mainland China
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash, cash equivalents and restricted cash and time deposits	101,590		70,418
China Hong Kong
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash, cash equivalents and restricted cash and time deposits	63,401		64,057
Korea
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash, cash equivalents and restricted cash and time deposits	1,068		3,934
Singapore
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash, cash equivalents and restricted cash and time deposits	$ 67		$ 67

v3.24.1.u1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Summary of Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Recurring
Assets
Cash and cash equivalents	$ 36,509	$ 37,518
Short-term investments	18,648	21,312
Total assets	55,157	58,830
Fair Value, Nonrecurring
Assets
Investments accounted for using measurement alternative		10,378
Total assets		10,378
Fair Value, Inputs, Level 1 | Fair Value, Recurring
Assets
Cash and cash equivalents	36,509	37,518
Short-term investments	18,648	21,312
Total assets	55,157	58,830
Fair Value, Inputs, Level 1 | Fair Value, Nonrecurring
Assets
Investments accounted for using measurement alternative		0
Total assets		0
Fair Value, Inputs, Level 2 | Fair Value, Recurring
Assets
Cash and cash equivalents	0	0
Short-term investments	0	0
Total assets	0	0
Fair Value, Inputs, Level 2 | Fair Value, Nonrecurring
Assets
Investments accounted for using measurement alternative		0
Total assets		0
Fair Value, Inputs, Level 3 | Fair Value, Recurring
Assets
Cash and cash equivalents	0	0
Short-term investments	0	0
Total assets	$ 0	0
Fair Value, Inputs, Level 3 | Fair Value, Nonrecurring
Assets
Investments accounted for using measurement alternative		10,378
Total assets		$ 10,378

v3.24.1.u1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Time Deposits (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Time Deposits [Abstract]
Time deposits	$ 76,205		$ 121,342
Interest income, deposits with financial institutions	$ 624	$ 975
Deposit in China Merchant Bank which matured on January 29, 2024 with an annual interest rate of 2.85%
Time Deposits [Abstract]
Time deposits, interest rate	2.85%
Time deposits	$ 0		29,797
Deposit in Bank of Ningbo which matured on February 17, 2024 with an annual interest rate of 2.85%
Time Deposits [Abstract]
Time deposits, interest rate	2.85%
Time deposits	$ 0		44,630
Deposit in Shanghai Pudong Development Bank which matures on October 20, 2025 with an annual interest rate of 3.10%
Time Deposits [Abstract]
Time deposits, interest rate	3.10%
Time deposits	$ 7,361		7,322
Deposit in Shanghai Pudong Development Bank which matures on November 14, 2025 with an annual interest rate of 3.10%
Time Deposits [Abstract]
Time deposits, interest rate	3.10%
Time deposits	$ 4,407		7,307
Deposit in Shanghai Pudong Development Bank which matures on December 8, 2025 with an annual interest rate of 3.10%
Time Deposits [Abstract]
Time deposits, interest rate	3.10%
Time deposits	$ 0		4,376
Deposit in Shanghai Pudong Development Bank which matures on December 15, 2025 with an annual interest rate of 3.10%
Time Deposits [Abstract]
Time deposits, interest rate	3.10%
Time deposits	$ 1,465		4,373
Deposit in Shanghai Pudong Development Bank which matures on December 30, 2025 with an annual interest rate of 3.10%
Time Deposits [Abstract]
Time deposits, interest rate	3.10%
Time deposits	$ 0		2,912
Deposit in China Industrial Bank which matures on January 3, 2026 with an annual interest rate of 3.15%
Time Deposits [Abstract]
Time deposits, interest rate	3.15%
Time deposits	$ 14,608		14,528
Deposit in China Everbright Bank which matures on December 5, 2024 with an annual interest rate of 5.38%
Time Deposits [Abstract]
Time deposits, interest rate	5.38%
Time deposits	$ 0		3,079
Deposit in China Everbright Bank which matures on May 22, 2024 with an annual interest rate of 5.28%
Time Deposits [Abstract]
Time deposits, interest rate	5.28%
Time deposits	$ 3,057		3,018
Deposit in China Everbright Bank which matured on April 5, 2024 with an annual interest rate of 5.33%
Time Deposits [Abstract]
Time deposits, interest rate	5.33%
Time deposits	$ 3,037		0
Deposit in China Merchant Bank, Lujiazui Branch which matures on May 27, 2024 with an annual interest rate of 1.85%
Time Deposits [Abstract]
Time deposits, interest rate	1.85%
Time deposits	$ 14,090		0
Deposit in China Merchant Bank, Huaihai Branch which matures on May 27, 2024 with an annual interest rate of 1.85%
Time Deposits [Abstract]
Time deposits, interest rate	1.85%
Time deposits	$ 14,090		0
Deposit in Bank of Ningbo which matures on September 11, 2024 with an annual interest rate of 1.50%
Time Deposits [Abstract]
Time deposits, interest rate	1.50%
Time deposits	$ 14,090		$ 0

v3.24.1.u1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Basic and Diluted Net Income per Common Share (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) class $ / shares shares	Mar. 31, 2023 USD ($) $ / shares shares
Numerator [Abstract]
Net income	$ 22,092	$ 8,963
Less: Net income attributable to non-controlling interests	4,659	1,818
Net income available to common stockholders, basic	17,433	7,145
Less: Dilutive effect arising from stock-based awards by ACM Shanghai	354	93
Net income available to common stockholders, diluted	$ 17,079	$ 7,052
Weighted average shares outstanding, basic (in shares) | shares	61,367,184	59,736,764
Effect of dilutive securities (in shares) | shares	4,875,137	5,322,013
Weighted average shares outstanding, diluted (in shares) | shares	66,242,321	65,058,777
Net income per common share [Abstract]
Basic (in dollars per share) | $ / shares	$ 0.28	$ 0.12
Diluted (in dollars per share) | $ / shares	$ 0.26	$ 0.11
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares) | shares	728,575	1,967,685
Classes of common stock outstanding | class	2

v3.24.1.u1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Concentration of Credit Risk (Details) - Customer Concentration Risk	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Revenue Benchmark | Two Customers
Concentration of Credit Risk [Abstract]
Concentration risk, percentage	55.90%
Revenue Benchmark | Four Customers
Concentration of Credit Risk [Abstract]
Concentration risk, percentage		59.70%
Accounts Receivable | Four Customers
Concentration of Credit Risk [Abstract]
Concentration risk, percentage	56.20%		59.10%

v3.24.1.u1

REVENUE FROM CONTRACTS WITH CUSTOMERS - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregated Revenue Information [Abstract]
Revenue (note 3)	$ 152,191	$ 74,256
Mainland China
Disaggregated Revenue Information [Abstract]
Revenue (note 3)	152,135	72,458
Other regions
Disaggregated Revenue Information [Abstract]
Revenue (note 3)	56	1,798
Single Wafer Cleaning, Tahoe and Semi-Critical Cleaning Equipment
Disaggregated Revenue Information [Abstract]
Revenue (note 3)	109,470	36,614
ECP (front-end and packaging), Furnace and Other Technologies
Disaggregated Revenue Information [Abstract]
Revenue (note 3)	25,800	26,598
Advanced Packaging (excluding ECP), Services & Spares
Disaggregated Revenue Information [Abstract]
Revenue (note 3)	$ 16,921	$ 11,044

v3.24.1.u1

REVENUE FROM CONTRACTS WITH CUSTOMERS - Accounts Receivables and Contract Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Accounts receivable	$ 296,371	$ 283,186
Advances from customers (note 3)	182,547	181,368
Deferred revenue (note 3)	$ 4,405	$ 3,687

v3.24.1.u1

REVENUE FROM CONTRACTS WITH CUSTOMERS - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Advances from customers	$ 2,182	$ 25,857
Contract with Customer, Liability, Revenue Recognized	29,188	$ 15,212
First-Tools
Disaggregation of Revenue [Line Items]
Advances from customers	$ 1,200

v3.24.1.u1

ACCOUNTS RECEIVABLE (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Accounts Receivable [Abstract]
Accounts receivable	$ 302,372	$ 288,016
Less: Allowance for credit losses	(6,001)	(4,830)
Total	296,371	$ 283,186
Accounts receivable [Abstract]
Increase accounts receivable	13,200
Increase in revenue	$ 77,900

v3.24.1.u1

ACCOUNTS RECEIVABLE - Summary of Allowance For Doubtful Accounts (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ (4,830)
Provision for credit losses	(1,171)
Ending balance	$ (6,001)

v3.24.1.u1

INVENTORIES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Inventory, Net [Abstract]
Raw materials	$ 256,332		$ 235,062
Work-in-process	61,871		81,438
Finished goods	262,937		228,895
Total inventory	581,140		545,395
Increase in raw materials and work in process	21,270
Increase in finished goods	$ 34,042
Inventory impairment, period	3 years
Inventory write-down	$ 1,025	$ 306
First-tools, Customer Ownership
Inventory, Net [Abstract]
Finished goods	$ 163,484		$ 123,390

v3.24.1.u1

PROPERTY, PLANT AND EQUIPMENT, NET (Details) ¥ in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2024 CNY (¥)	Dec. 31, 2023 USD ($)
Property, Plant and Equipment, Net, by Type [Abstract]
Property cost	$ 113,059			$ 112,911
Less: Total accumulated depreciation and amortization	(19,531)			(17,503)
Construction in progress	125,294			106,440
Total property, plant and equipment, net	218,822			201,848
Depreciation and amortization expense	2,475	$ 1,714
Buildings and plants
Property, Plant and Equipment, Net, by Type [Abstract]
Property cost	82,933			83,109
Buildings and plants | ACM Lingang
Property, Plant and Equipment, Net, by Type [Abstract]
Property cost	35,189		¥ 249,746
Buildings and plants | ACM Shanghai
Property, Plant and Equipment, Net, by Type [Abstract]
Property cost	47,744		¥ 338,848
Manufacturing equipment
Property, Plant and Equipment, Net, by Type [Abstract]
Property cost	16,702			16,556
Office equipment
Property, Plant and Equipment, Net, by Type [Abstract]
Property cost	5,061			4,953
Transportation equipment
Property, Plant and Equipment, Net, by Type [Abstract]
Property cost	402			404
Leasehold improvement
Property, Plant and Equipment, Net, by Type [Abstract]
Property cost	$ 7,961			$ 7,889

v3.24.1.u1

LAND USE RIGHT, NET - Summary of Land Use Right (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Land Use Right, Net [Abstract]
Land use right purchase amount	$ 8,977	$ 8,996
Less: accumulated amortization	(672)	(629)
Land use right, net	$ 8,305	$ 8,367

v3.24.1.u1

LAND USE RIGHT, NET - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Land Use Right, Net [Abstract]
Amortization	$ 43	$ 50

v3.24.1.u1

LAND USE RIGHT, NET - Summary of Future Amortization (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Annual Amortization of Land use Right [Abstract]
remainder of 2024	$ 135
2025	180
2026	180
2027	180
2028	180
2029 and thereafter	7,450
Land use right, net	$ 8,305	$ 8,367

v3.24.1.u1

OTHER LONG-TERM ASSETS - Summary of Other Long-term Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Other Assets, Noncurrent Disclosure [Abstract]
Prepayments for property, plant and equipment	$ 7,690	$ 3,380
Lease deposits	867	834
Security deposit for land use right	695	696
Others	1,219	1,140
Total other long-term assets	$ 10,471	$ 6,050

v3.24.1.u1

OTHER LONG-TERM ASSETS - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property cost	$ 113,059	$ 112,911
Buildings and plants
Property, Plant and Equipment [Line Items]
Property cost	$ 82,933	$ 83,109

v3.24.1.u1

SHORT-TERM BORROWINGS (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Short-Term Borrowings [Abstract]
Short-term debt	$ 54,706		$ 31,335
Interest expense related to short-term borrowings	213	$ 490
Line of Credit up to RMB 150,000 from China Everbright Bank
Short-Term Borrowings [Abstract]
Line of credit facility, maximum borrowing capacity	$ 150,000		$ 150,000
Line of Credit, due on August 29, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 2,459		$ 2,463
Line of Credit up to RMB 40,000 from Bank of China,
Short-Term Borrowings [Abstract]
Line of credit facility, maximum borrowing capacity	$ 40,000		$ 40,000
Line of Credit, due on September 7, 2024 with an annual interest rate of 2.87%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	2.87%		2.87%
Short-term debt	$ 5,640		$ 5,648
Line of Credit up to RMB 200,000 from China Merchants Bank
Short-Term Borrowings [Abstract]
Line of credit facility, maximum borrowing capacity	$ 200,000		$ 200,000
Line of Credit, China Merchants Bank, due on August 7, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,271
Line of Credit, China Merchants Bank, due on August 8, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,271
Line of Credit, China Merchants Bank, due on August 9, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,271
Line of Credit, China Merchants Bank, due on August 14, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,271
Line of Credit, China Merchants Bank, due on August 17, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,271
Line of Credit, China Merchants Bank, due on August 20, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,271
Line of Credit, China Merchants Bank, due on August 21, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,271
Line of Credit, China Merchants Bank, due on August 22, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,271
Line of Credit, China Merchants Bank, due on August 24, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,271
Line of Credit, China Merchants Bank, due on August 27, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,271
Line of Credit, China Merchants Bank, due on August 29, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,271
Line of Credit, China Merchants Bank, due on August 30, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,271
Line of Credit, China Merchants Bank, due on September 3, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,271
Line of Credit, China Merchants Bank, due on September 5, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,270
Line of Credit, China Merchants Bank, due on September 6, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,270
Line of Credit, China Merchants Bank, due on September 10, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,270
Line of Credit, China Merchants Bank, due on September 12, 2024 with an annual interest rate of 3.00%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	3.00%		3.00%
Short-term debt	$ 1,269		$ 1,270
Line Of Credit, China Merchants Bank, Due On February 27, 2025 With An Annual Interest Rate Of 2.60%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	2.60%
Short-term debt	$ 1,340		0
Line Of Credit, China Merchants Bank, Due On February 28, 2025 With An Annual Interest Rate Of 2.60%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	2.60%
Short-term debt	$ 1,340		0
Line Of Credit, China Merchants Bank, Due On March 1, 2025 With An Annual Interest Rate Of 2.60%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	2.60%
Short-term debt	$ 1,340		0
Line Of Credit, China Merchants Bank, Due On March 5, 2025 With An Annual Interest Rate Of 2.60%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	2.60%
Short-term debt	$ 1,340		0
Line Of Credit, China Merchants Bank, Due On March 8, 2025 With An Annual Interest Rate Of 2.60%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	2.60%
Short-term debt	$ 1,270		0
Line Of Credit Up To RMB 120,000 From Bank Of China
Short-Term Borrowings [Abstract]
Line of credit facility, maximum borrowing capacity	$ 120,000
Line Of Credit, Bank Of China, Due On March 20, 2025 With An Annual Interest Rate Of 2.75%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	2.75%
Short-term debt	$ 16,921		0
Line Of Credit Up To KRW 500,000 from Industrial Bank Of Korea
Short-Term Borrowings [Abstract]
Line of credit facility, maximum borrowing capacity	$ 500,000
Line Of Credit Due On July 12, 2024 With An Annual Interest Rate Of 6.03%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	6.03%
Short-term debt	$ 0		77
Line Of Credit Up To KRW 2,000,000 From Industrial Bank Of Korea
Short-Term Borrowings [Abstract]
Line of credit facility, maximum borrowing capacity	$ 2,000,000		$ 2,000,000
Line Of Credit Due On December 15, 2024 With An Annual Interest Rate Of 4.29%
Short-Term Borrowings [Abstract]
Line of credit facility, interest rate during period	4.27%		4.27%
Short-term debt	$ 1,483		$ 1,544

v3.24.1.u1

OTHER PAYABLES AND ACCRUED EXPENSES - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued commissions	$ 15,932	$ 15,572
Accrued warranty	11,339	9,834
Accrued payroll	16,550	14,840
Accrued professional fees	113	696
Accrued machine testing fees	1,863	1,762
Accrued machine sales fees	4,942	6,010
Accrued Lingang construction fees	33,546	33,729
Others	22,813	20,508
Current portion of long-term borrowings (note 12)	$ 107,098	$ 102,951

v3.24.1.u1

LEASES - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Components of lease expense [Abstract]
Operating lease cost	$ 973	$ 488
Short-term lease cost	321	282
Total lease cost	$ 1,294	$ 770

v3.24.1.u1

LEASES - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash paid for amounts included in the measurement of lease liabilities [Abstract]
Operating cash outflow from operating leases	$ 973	$ 488
Operating lease right-of-use assets obtained in exchange for new operating lease liabilities	$ 80	$ 6,592

v3.24.1.u1

LEASES - Maturities of Lease Liabilities (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Maturities of outstanding lease liabilities [Abstract]
remainder of 2024	$ 2,370
2025	1,800
2026	1,215
2027	1,148
2028 and thereafter	595
Total lease payments	7,128
Less: Interest	(630)
Present value of lease liabilities	$ 6,498

v3.24.1.u1

LEASES - Weighted Average Remaining Lease Term (Details)	Mar. 31, 2024	Dec. 31, 2023
Lessee, Operating Lease, Description [Abstract]
Weighted average remaining lease term (years)	3 years 4 months 13 days	3 years 5 months 8 days
Weighted average discount rate	3.87%	3.91%

v3.24.1.u1

LONG-TERM BORROWINGS - Summary of Long-term Borrowings (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) installment loan	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Long-Term Borrowings [Abstract]
Long-term debt	$ 59,957		$ 60,735
Less: Current portion	(6,549)		(6,783)
Long-term Borrowings	53,408		53,952
Long-term debt	59,957		60,735
Long-term debt, fair value	56,409		56,462
Interest costs incurred	570	$ 189
China Merchants Bank
Long-Term Borrowings [Abstract]
Long-term debt	$ 12,919		13,362
Number of installments for loan repayable | installment	120
Line of credit facility, interest rate during period	3.95%
Long-term debt	$ 12,919		13,362
Bank of China
Long-Term Borrowings [Abstract]
Long-term debt	$ 4,759		5,013
Number of installments for loan repayable | installment	6
Line of credit facility, interest rate during period	2.60%
Number of loans | loan	2
Long-term debt	$ 4,759		5,013
Bank of Shanghai
Long-Term Borrowings [Abstract]
Long-term debt	$ 14,101		14,120
Line of credit facility, interest rate during period	2.85%
Long-term debt	$ 14,101		14,120
Citic Bank
Long-Term Borrowings [Abstract]
Long-term debt	28,178		28,240
Long-term debt	$ 28,178		$ 28,240
Citic Bank | Lone One
Long-Term Borrowings [Abstract]
Number of installments for loan repayable | installment	4
Line of credit facility, interest rate during period	3.10%
Citic Bank | Loan Two
Long-Term Borrowings [Abstract]
Number of installments for loan repayable | installment	4
Line of credit facility, interest rate during period	4.50%

v3.24.1.u1

LONG-TERM BORROWINGS - Summary of Scheduled Principal Payments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Principal Payments of Long-Term Loan [Abstract]
2023	$ 6,120
2025	43,993
2026	1,851
2027	1,925
2028	2,003
Thereafter	4,065
Long-term debt	$ 59,957	$ 60,735

v3.24.1.u1

OTHER LONG-TERM LIABILITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Other Long-term Liabilities [Abstract]
Other long-term liabilities	$ 5,469	$ 5,873
Subsidies to Stress Free Polishing project, commenced in 2008 and 2017
Other Long-term Liabilities [Abstract]
Other long-term liabilities	189	475
Subsidies to other cleaning tools, commenced in 2020
Other Long-term Liabilities [Abstract]
Other long-term liabilities	647	632
Subsidies to SW Lingang R&D development in 2021
Other Long-term Liabilities [Abstract]
Other long-term liabilities	3,454	3,467
Other
Other Long-term Liabilities [Abstract]
Other long-term liabilities	$ 1,179	$ 1,299

v3.24.1.u1

LONG-TERM INVESTMENT - Narrative (Details) ¥ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2024 CNY (¥)
Investments [Abstract]
Loss from equity method investments (note 14)	$ 520,000	$ 32,000
Dividends from unconsolidated affiliates	600,000	$ 0
Equity Investment | Ninebell | Class A Common Stock
Investments [Abstract]
Investment purchase price	$ 1,200,000
Percent ownership by ACM and subsidiaries	20.00%		20.00%
Equity Investment | Wooil | Class A Common Stock
Investments [Abstract]
Investment purchase price	$ 1,000,000
Percent ownership by ACM and subsidiaries	20.00%		20.00%
Equity Investment | Hefei Shixi | Class A Common Stock
Investments [Abstract]
Investment purchase price	$ 4,200,000		¥ 30,000
Percent ownership by ACM and subsidiaries	10.00%		10.00%
Equity Investment | Shengyi | Class A Common Stock
Investments [Abstract]
Investment purchase price	$ 109,000
Percent ownership by ACM and subsidiaries	14.00%		14.00%
Equity Investment | Company D | Class A Common Stock
Investments [Abstract]
Investment purchase price	$ 4,230,000		¥ 30,000
Percent ownership by ACM and subsidiaries	16.70%		16.70%
Equity Investment | Company A | Class A Common Stock
Investments [Abstract]
Investment purchase price	$ 4,200,000		¥ 30,000
Percent ownership by ACM and subsidiaries	4.40%		4.40%
Equity Investment | Company B | Class A Common Stock
Investments [Abstract]
Investment purchase price	$ 930,000		¥ 6,600
Percent ownership by ACM and subsidiaries	1.40%		1.40%
Equity Investment | Company C | Class A Common Stock
Investments [Abstract]
Investment purchase price	$ 1,760,000		¥ 12,500
Percent ownership by ACM and subsidiaries	5.00%		5.00%
Equity Investment | Waferworks | Class A Common Stock
Investments [Abstract]
Investment purchase price	$ 1,568,000
Percent ownership by ACM and subsidiaries	0.30%		0.30%
Equity Investment | Shengyi | Class A Common Stock
Investments [Abstract]
Investment purchase price	$ 860,000		¥ 6,100
Percent ownership by ACM and subsidiaries	1.00%		1.00%

v3.24.1.u1

LONG-TERM INVESTMENT - Summary of Long Term Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Long-Term Investments [Line Items]
Long-term investments (note 14)	$ 31,293	$ 27,880
Equity investee:
Long-Term Investments [Line Items]
Long-term investments (note 14)	20,584	17,502
Equity investee: | Ninebell
Long-Term Investments [Line Items]
Long-term investments (note 14)	5,481	5,632
Equity investee: | Wooil
Long-Term Investments [Line Items]
Long-term investments (note 14)	989	1,003
Equity investee: | Shengyi
Long-Term Investments [Line Items]
Long-term investments (note 14)	1,999	1,693
Equity investee: | Hefei Shixi
Long-Term Investments [Line Items]
Long-term investments (note 14)	7,888	9,174
Equity investee: | Company D
Long-Term Investments [Line Items]
Long-term investments (note 14)	4,227	0
Investments accounted for using measurement alternative:
Long-Term Investments [Line Items]
Long-term investments (note 14)	31,293	27,880
Investments accounted for using measurement alternative: | Shengyi
Long-Term Investments [Line Items]
Long-term investments (note 14)	856	857
Investments accounted for using measurement alternative: | Waferworks
Long-Term Investments [Line Items]
Long-term investments (note 14)	0	1,412
Investments accounted for using measurement alternative: | Company A
Long-Term Investments [Line Items]
Long-term investments (note 14)	4,227	4,236
Investments accounted for using measurement alternative: | Company B
Long-Term Investments [Line Items]
Long-term investments (note 14)	930	932
Investments accounted for using measurement alternative: | Company C
Long-Term Investments [Line Items]
Long-term investments (note 14)	1,761	0
Investments accounted for using measurement alternative: | Other
Long-Term Investments [Line Items]
Long-term investments (note 14)	$ 2,935	$ 2,941

v3.24.1.u1

SHORT-TERM INVESTMENTS - Narrative (Details) ¥ in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2024 CNY (¥)	Feb. 29, 2024 USD ($)	Feb. 29, 2024 CNY (¥)	Dec. 31, 2023	Jul. 31, 2023 USD ($)	Jul. 31, 2023 CNY (¥)	Sep. 27, 2022 USD ($)	Sep. 27, 2022 CNY (¥)	Sep. 19, 2022 USD ($)	Sep. 19, 2022 CNY (¥)	Dec. 31, 2021 USD ($)
Investments [Abstract]
Proceeds from sale of short-term investments (note 15)	$ 0	$ 11,072
Sale of short-term investments receivable	3,167		¥ 22,478
Realized gain from sale of short-term investments (note 15)	273	3,994
Nuode Asset Management Company Limited
Investments [Abstract]
Investment in partnership	3,167		22,478						$ 4,196	¥ 30,000	$ 22,160	¥ 160,000
Ownership percentage in partnership						18.75%			18.75%	18.75%
SMIC
Investments [Abstract]
Proceeds from sale of short-term investments (note 15)		11,072
Realized gain from sale of short-term investments (note 15)	273	$ 3,994
Huahong Semiconductor Limited
Investments [Abstract]
Investment in partnership							$ 13,930	¥ 100,000
Zhongiuxin Limited Company
Investments [Abstract]
Investment in partnership	4,179		30,000
Shanghai Syncrystalline Silicon Materials Co., Ltd
Investments [Abstract]
Investment in partnership	$ 2,818		¥ 20,000	$ 1,409	¥ 10								$ 1,409

v3.24.1.u1

SHORT-TERM INVESTMENTS - Summary of Trading Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Cost	$ 21,135	$ 20,155
Market value	$ 18,648	$ 21,312

v3.24.1.u1

SHORT-TERM INVESTMENTS - Summary of Unrealized Gain (Loss) on Trading Securities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Trading, Unrealized Gain (Loss)	$ (2,595)	$ (654)
Debt Securities, Trading, Realized Gain (Loss)	273	3,994
Debt Securities, Unrealized Gain (Loss)	$ (2,322)	$ 3,340

v3.24.1.u1

RELATED PARTY BALANCES AND TRANSACTIONS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Related Party Transaction [Line Items]
Purchase of materials	$ 15,144	$ 18,370
Cost of revenue, including cost of revenue from related parties of $15.1 million and $18.4 million for the three months ended March 31, 2024 and 2023, respectively (note 16)	73,070	34,270
Ninebell
Related Party Transaction [Line Items]
Purchase of materials	14,152	16,397
Shengyi
Related Party Transaction [Line Items]
Purchase of materials	992	1,973
Related Party
Related Party Transaction [Line Items]
Other receivables	1,338		$ 2,432
Accounts payable	16,243		11,407
Cost of revenue, including cost of revenue from related parties of $15.1 million and $18.4 million for the three months ended March 31, 2024 and 2023, respectively (note 16)	15,100	18,400
Related Party | Ninebell
Related Party Transaction [Line Items]
Other receivables	1,338		2,432
Accounts payable	12,571		7,624
Related Party | Shengyi
Related Party Transaction [Line Items]
Accounts payable	3,672		$ 3,783
Cost of revenue, including cost of revenue from related parties of $15.1 million and $18.4 million for the three months ended March 31, 2024 and 2023, respectively (note 16)	$ 73	$ 278

v3.24.1.u1

COMMON STOCK (Details)	3 Months Ended
	Mar. 31, 2024 vote $ / shares shares	Mar. 31, 2023 shares	Dec. 31, 2023 shares	Dec. 31, 2022 shares
Common Stock Class A
Class of Stock Disclosures [Abstract]
Common stock, shares authorized (in shares)	150,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001
Number of votes for each share entitled | vote	1
Exercise of stock options (in shares)		163,069
Common stock issued (in shares)	56,986,777		56,036,172
Common stock outstanding (in shares)	56,986,777		56,036,172
Class B Common Stock
Class of Stock Disclosures [Abstract]
Common stock, shares authorized (in shares)	5,307,816
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001
Number of votes for each share entitled | vote	20
Shares converted	1
Common stock issued (in shares)	5,021,811		5,021,811
Common stock outstanding (in shares)	5,021,811		5,021,811
Common Stock | Common Stock Class A
Class of Stock Disclosures [Abstract]
Exercise of stock options (in shares)	950,605	163,069
Common stock outstanding (in shares)	56,986,777	54,818,355	56,036,172	54,655,286
Common Stock | Class B Common Stock
Class of Stock Disclosures [Abstract]
Common stock outstanding (in shares)	5,021,811	5,021,811	5,021,811	5,021,811

v3.24.1.u1

STOCK-BASED COMPENSATION, Share Option Activities (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	May 31, 2023	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Employee Share Option
Number of Option Share [Roll Forward]
Outstanding, beginning of period (in shares)		9,998,637
Granted (in shares)		3,000
Exercised (in shares)		(851,954)
Forfeited/cancelled (in shares)		(24,330)
Outstanding, end of period (in shares)		9,125,353		9,998,637
Vested and exercisable (in shares)		5,278,784
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share)		$ 5.15
Granted (in dollars per share)		23.95
Exercised (in dollars per share)		2.7
Forfeited/cancelled (in dollars per share)		11.14
Outstanding at end of period (in dollars per share)		5.37		$ 5.15
Weighted Average Exercise Price
Outstanding, beginning of period (in dollars per share)		9.59
Granted (in dollars per share)		31.92
Exercised (in dollars per share)		5.74
Forfeited/cancelled (in dollars per share)		23.08
Outstanding, end of period (in dollars per share)		$ 9.79		$ 9.59
Weighted Average Remaining Contractual Term
Weighted average remaining contractual term		6 years 25 days		6 years 2 months 1 day
Unrecognized employee stock-based compensation expense		$ 24,670		$ 27,152
Cost not yet recognized		3 years 9 months 18 days	4 years
Intrinsic value		$ 21,865
Intrinsic value, outstanding		178,674
Intrinsic value, exercisable		$ 117,476
Employee Share Option | ACM Shanghai
Number of Option Share [Roll Forward]
Exercised (in shares)	(2,150,309)
Weighted Average Remaining Contractual Term
Weighted average remaining contractual term		1 year 9 months 18 days		2 years 1 month 6 days
Unrecognized employee stock-based compensation expense		$ 65,682		$ 79,882
Employee Share Option | ACM Shanghai | 2019 Stock Option Incentive Plan
Number of Option Share [Roll Forward]
Outstanding, beginning of period (in shares)		3,134,883
Forfeited/cancelled (in shares)		(92,308)
Outstanding, end of period (in shares)		3,042,575		3,134,883
Vested and exercisable (in shares)		3,042,575
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share)		$ 0.24
Forfeited/cancelled (in dollars per share)		0.24
Outstanding at end of period (in dollars per share)		0.24		$ 0.24
Weighted Average Exercise Price
Outstanding, beginning of period (in dollars per share)		1.85
Forfeited/cancelled (in dollars per share)		1.85
Outstanding, end of period (in dollars per share)		$ 1.85		$ 1.85
Weighted Average Remaining Contractual Term
Weighted average remaining contractual term		7 months 24 days		10 months 6 days
Intrinsic value		$ 0
Intrinsic value, outstanding		31,616
Intrinsic value, exercisable		$ 31,616
Employee Share Option | ACM Shanghai | 2023 Stock Option Incentive Plan
Number of Option Share [Roll Forward]
Outstanding, beginning of period (in shares)		10,575,500
Forfeited/cancelled (in shares)		(84,000)
Outstanding, end of period (in shares)		10,491,500		10,575,500
Vested and exercisable (in shares)		0
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share)		$ 9.49
Forfeited/cancelled (in dollars per share)		9.49
Outstanding at end of period (in dollars per share)		9.12		$ 9.49
Weighted Average Exercise Price
Outstanding, beginning of period (in dollars per share)		7.06
Forfeited/cancelled (in dollars per share)		7.06
Outstanding, end of period (in dollars per share)		$ 7.01		$ 7.06
Weighted Average Remaining Contractual Term
Weighted average remaining contractual term		2 years 10 months 2 days		3 years 1 month 2 days
Intrinsic value		$ 0
Intrinsic value, outstanding		54,686
Intrinsic value, exercisable		$ 0
Non-Employee Stock Option
Number of Option Share [Roll Forward]
Outstanding, beginning of period (in shares)		1,170,795
Exercised (in shares)		(98,651)
Forfeited/cancelled (in shares)		(1,903)
Outstanding, end of period (in shares)		1,070,241		1,170,795
Vested and exercisable (in shares)		1,070,241
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share)		$ 0.42
Exercised (in dollars per share)		0.22
Forfeited/cancelled (in dollars per share)		0.22
Outstanding at end of period (in dollars per share)		0.44		$ 0.42
Weighted Average Exercise Price
Outstanding, beginning of period (in dollars per share)		1.31
Exercised (in dollars per share)		0.50
Forfeited/cancelled (in dollars per share)		0.50
Outstanding, end of period (in dollars per share)		$ 1.39		$ 1.31
Weighted Average Remaining Contractual Term
Weighted average remaining contractual term		2 years 6 months 3 days		2 years 7 months 28 days
Unrecognized employee stock-based compensation expense		$ 0		$ 9
Cost not yet recognized		0 years		2 months 12 days
Intrinsic value		$ 2,756
Intrinsic value, outstanding		29,702
Intrinsic value, exercisable		$ 29,702

v3.24.1.u1

STOCK-BASED COMPENSATION, Assumptions Used to Determine Fair Value of Share Options Granted (Details) - Employee Share Option - Service Period Based	3 Months Ended
	Mar. 31, 2024 $ / shares
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Fair value of common share (in dollars per share)	$ 31.92
Expected term	6 years 3 months
Expected volatility rate	85.48%
Risk free interest rate	4.23%
Expected dividend rate	0.00%

v3.24.1.u1

STOCK-BASED COMPENSATION - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	$ 14,569	$ 2,068
Employee Stock Option Plan
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	2,353	2,018
Employee Stock Option Plan | ACM Shanghai
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	12,207	39
Non-Employee Stock Option Plan
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	9	11
Cost of revenue
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	781	125
Sales and marketing expense
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	3,027	431
Research and development expense
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	4,503	701
General and administrative expense
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	$ 6,258	$ 811

v3.24.1.u1

INCOME TAXES - Narrative (Details) $ in Thousands	3 Months Ended		48 Months Ended
	Mar. 31, 2024 USD ($) subsidiary	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Income Taxes [Abstract]
Income tax expense	$ 4,369	$ 2,879
Capitalized contract cost, amortization period	15 years
Unrecognized tax benefits	$ 13,026		$ 13,026
Unrecognized tax benefits that would impact effective tax rate	12,943		$ 12,943
Interest or penalties	$ 338	$ 284
Number of subsidiaries | subsidiary	4
ACM Research (Shanghai), Inc. ("ACM Shanghai")
Income Taxes [Abstract]
Foreign corporate tax rate	15.00%
Foreign Tax Authority
Income Taxes [Abstract]
Foreign corporate tax rate	25.00%
Effective period of preferential income tax rate	3 years
Foreign Tax Authority | Minimum
Income Taxes [Abstract]
Foreign corporate tax rate	15.00%
Foreign Tax Authority | Maximum
Income Taxes [Abstract]
Foreign corporate tax rate	25.00%
Foreign Tax Authority | ACM Research (Shanghai), Inc. ("ACM Shanghai")
Income Taxes [Abstract]
Foreign corporate tax rate			12.50%
Foreign Tax Authority | ACM Research (Shanghai), Inc. ("ACM Shanghai") | Minimum
Income Taxes [Abstract]
Foreign corporate tax rate	15.00%
Foreign Tax Authority | ACM Research (Wuxi), Inc. ("ACM Wuxi")
Income Taxes [Abstract]
Foreign corporate tax rate	25.00%
Foreign Tax Authority | ACM Research (Beijing), Inc. ("ACM Beijing")
Income Taxes [Abstract]
Foreign corporate tax rate	25.00%
Foreign Tax Authority | ACM Research ( Lingang), Inc. ("ACM Lingang") (1)
Income Taxes [Abstract]
Foreign corporate tax rate	15.00%

v3.24.1.u1

INCOME TAXES - Summary of Income Tax Benefit (Expense) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Total income tax benefit (expense)	$ (4,369)	$ (2,879)

v3.24.1.u1

COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands, ¥ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) legalProceeding	Mar. 31, 2024 CNY (¥)	Mar. 31, 2024 CNY (¥) legalProceeding	Dec. 31, 2023 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Contractual obligation	$ 24,285			$ 30,936
Other commitment	1,409			7,413
Damages awarded	$ 62,600	¥ 450.0
Land use rights period	6 years	6 years
Annual total taxes	$ 22,000	¥ 157.6
Investments	$ 132,014			$ 116,932
Security deposit refund percentage	20.00%		20.00%
Security deposit	$ 400		¥ 2.5
Number of outstanding legal proceedings | legalProceeding	0		0

v3.24.1.u1

SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) segment	Dec. 31, 2023 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment	1
Geographic Areas, Long-Lived Assets [Abstract]
Long-lived assets	$ 244,097	$ 223,191
Number of Operating Segments | segment	1
Mainland China
Geographic Areas, Long-Lived Assets [Abstract]
Long-lived assets	$ 231,208	209,725
Korea
Geographic Areas, Long-Lived Assets [Abstract]
Long-lived assets	11,630	12,190
United States
Geographic Areas, Long-Lived Assets [Abstract]
Long-lived assets	$ 1,259	$ 1,276

v3.24.1.u1

STATUTORY SURPLUS RESERVE (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Retained Earnings (Accumulated Deficit) [Abstract]
Statutory surplus reserve	$ 30,060	$ 30,060
ACM Research (Shanghai), Inc. ("ACM Shanghai")
Retained Earnings (Accumulated Deficit) [Abstract]
Statutory surplus reserve	$ 30,060	$ 30,060

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