0001140361-21-027398 | 10-Q | XBRL Viewer

Print Document View Excel Document

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2021	Aug. 03, 2021
Document Information [Line Items]
Entity Registrant Name	ACM Research, Inc.
Entity Central Index Key	0001680062
Current Fiscal Year End Date	--12-31
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Document Transition Report	false
Entity File Number	001-38273
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
Class A Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		17,680,409
Class B Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		1,707,605

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 70,209	$ 71,766
Trading securities (note 16)	31,257	28,239
Accounts receivable, less allowance for doubtful accounts of $0 as of June 30, 2021 and December 31, 2020 (note 4)	71,357	56,441
Other receivables	10,733	9,679
Inventories (note 5)	136,852	88,639
Prepaid expenses	8,953	5,892
Total current assets	329,361	260,656
Property, plant and equipment, net (note 6)	8,985	8,192
Land use right, net (note 7)	9,642	9,646
Operating lease right-of-use assets, net (note 11)	5,209	4,297
Intangible assets, net	630	554
Deferred tax assets (note 21)	14,691	11,076
Long-term investments (note 14)	7,006	6,340
Other long-term assets (note 8)	43,434	40,496
Total assets	418,958	341,257
Current liabilities:
Short-term borrowings (note 9)	22,162	26,147
Current portion of long-term borrowings (note 12)	1,799	1,591
Accounts payable	67,031	35,603
Advances from customers	43,845	17,888
Deferred revenue	2,348	1,343
Income taxes payable (note 21)	482	31
FIN-48 payable (note 21)	83	83
Other payables and accrued expenses (note 10)	21,871	18,805
Current portion of operating lease liability (note 11)	2,437	1,417
Total current liabilities	162,058	102,908
Long-term borrowings (note 12)	18,717	17,979
Long-term operating lease liability (note 11)	2,772	2,880
Deferred tax liability (note 21)	1,298	1,286
Other long-term liabilities (note 13)	4,557	8,034
Total liabilities	189,402	133,087
Commitments and contingencies (note 21)
Stockholders' equity:
Additional paid in capital	108,566	102,004
Accumulated surplus	46,324	34,287
Accumulated other comprehensive income	5,931	4,857
Total ACM Research, Inc. stockholders' equity	160,823	141,150
Non-controlling interests	68,733	67,020
Total stockholders' equity	229,556	208,170
Total liabilities and stockholders' equity	418,958	341,257
Class A Common Stock [Member]
Stockholders' equity:
Common stock	2	2
Class B Common Stock [Member]
Stockholders' equity:
Common stock	$ 0	$ 0

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Accounts receivable, allowance for doubtful accounts	$ 0	$ 0
Class A Common Stock [Member]
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	17,668,409	16,896,693
Common stock, shares outstanding (in shares)	17,668,409	16,896,693
Class B Common Stock [Member]
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	2,409,738	2,409,738
Common stock, shares issued (in shares)	1,707,605	1,802,606
Common stock, shares outstanding (in shares)	1,707,605	1,802,606

Condensed Consolidated Statements of Operations and Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Condensed Consolidated Statements of Operations and Comprehensive Income [Abstract]
Revenue (note 3)	$ 53,864	$ 39,049	$ 97,596	$ 63,397
Cost of revenue	32,184	19,693	57,871	33,813
Gross profit	21,680	19,356	39,725	29,584
Operating expenses:
Sales and marketing	5,789	4,595	11,097	7,600
Research and development	7,933	5,221	13,437	8,898
General and administrative	3,627	2,204	7,410	4,532
Total operating expenses, net	17,349	12,020	31,944	21,030
Income from operations	4,331	7,336	7,781	8,554
Interest income	31	320	80	655
Interest expense	(194)	(228)	(383)	(339)
Change in fair value of financial liability	0	(5,431)	0	(5,431)
Unrealized gain on trading securities	3,783	0	2,736	0
Other income (expenses), net	(897)	149	(428)	826
Equity income in net income of affiliates	295	209	615	357
Income before income taxes	7,349	2,355	10,401	4,622
Income tax benefit (expense) (note 21)	(15)	(1,859)	2,755	(2,163)
Net income	7,334	496	13,156	2,459
Less: Net income attributable to non-controlling interests and redeemable non-controlling interests	767	577	1,119	835
Net income (loss) attributable to ACM Research, Inc.	6,567	(81)	12,037	1,624
Comprehensive income:
Net income	7,334	496	13,156	2,459
Foreign currency translation adjustment	3,000	242	1,668	(1,658)
Comprehensive Income	10,334	738	14,824	801
Less: Comprehensive income attributable to non-controlling interests and redeemable non-controlling interests	1,797	1,610	1,714	916
Comprehensive income (loss) attributable to ACM Research, Inc.	$ 8,537	$ (872)	$ 13,110	$ (115)
Net income (loss) attributable to ACM Research, Inc. per common share (note 2):
Basic (in dollars per share)	$ 0.34	$ 0.00	$ 0.63	$ 0.09
Diluted (in dollars per share)	$ 0.30	$ 0.00	$ 0.56	$ 0.08
Weighted average common shares outstanding used in computing per share amounts (note 2):
Basic (in shares)	19,123,659	18,050,841	18,956,195	18,085,602
Diluted (in shares)	21,807,744	21,516,175	21,679,528	21,197,203

Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member] Common Stock Class A [Member]	Common Stock [Member] Common Stock Class B [Member]	Additional Paid-in Capital [Member]	Accumulated Surplus [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]	Total
Beginning balance at Dec. 31, 2019	$ 2	$ 0	$ 83,487	$ 15,507	$ (1,675)	$ 0	$ 97,321
Beginning balance (in shares) at Dec. 31, 2019	16,182,151	1,862,608
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 0	$ 0	0	1,624	0	192	1,816
Foreign currency translation adjustment	0	0	0	0	(1,740)	928	(812)
Exercise of stock options	$ 0	$ 0	873	0	0	0	873
Exercise of stock options (in shares)	185,903	0
Stock-based compensation	$ 0	$ 0	1,544	0	0	0	1,544
Conversion of class B common stock to Class A common stock	$ 0	$ 0	0	0	0	0	0
Conversion of class B common stock to Class A common stock (in shares)	60,002	(60,002)
Share repurchase	$ 0	$ 0	(9,715)	0	0	0	(9,715)
Share repurchase (in shares)	(242,681)	0
Exercise of stock warrants	$ 0	$ 0	0	0	0	0	0
Exercise of stock warrants (in shares)	64,717	0
Reclassification of redeemable non-controlling interest	$ 0	$ 0	0	0	0	59,958	59,958
Ending balance at Jun. 30, 2020	$ 2	$ 0	76,189	17,131	(3,415)	61,078	150,985
Ending balance (in shares) at Jun. 30, 2020	16,250,092	1,802,606
Beginning balance at Mar. 31, 2020	$ 2	$ 0	84,351	17,212	(2,623)	0	98,942
Beginning balance (in shares) at Mar. 31, 2020	16,317,346	1,862,608
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 0	$ 0	0	(81)	0	192	111
Foreign currency translation adjustment	0	0	0	0	(792)	928	136
Exercise of stock options	$ 0	$ 0	698	0	0	0	698
Exercise of stock options (in shares)	115,425	0
Stock-based compensation	$ 0	$ 0	855	0	0	0	855
Conversion of class B common stock to Class A common stock	$ 0	$ 0	0	0	0	0	0
Conversion of class B common stock to Class A common stock (in shares)	60,002	(60,002)
Share repurchase	$ 0	$ 0	(9,715)	0	0	0	(9,715)
Share repurchase (in shares)	(242,681)	0
Reclassification of redeemable non-controlling interest	$ 0	$ 0	0	0	0	59,958	59,958
Ending balance at Jun. 30, 2020	$ 2	$ 0	76,189	17,131	(3,415)	61,078	150,985
Ending balance (in shares) at Jun. 30, 2020	16,250,092	1,802,606
Beginning balance at Dec. 31, 2020	$ 2	$ 0	102,004	34,287	4,857	67,020	208,170
Beginning balance (in shares) at Dec. 31, 2020	16,896,693	1,802,606
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 0	$ 0	0	12,037	0	1,119	13,156
Foreign currency translation adjustment	0	0	0	0	1,074	594	1,668
Exercise of stock options	$ 0	$ 0	2,197	0	0	0	2,197
Exercise of stock options (in shares)	434,034	0
Stock-based compensation	$ 0	$ 0	2,545	0	0	0	2,545
Conversion of class B common stock to Class A common stock	$ 0	$ 0	0	0	0	0	0
Conversion of class B common stock to Class A common stock (in shares)	95,001	(95,001)
Exercise of stock warrants	$ 0	$ 0	1,820	0	0	0	1,820
Exercise of stock warrants (in shares)	242,681	0
Ending balance at Jun. 30, 2021	$ 2	$ 0	108,566	46,324	5,931	68,733	229,556
Ending balance (in shares) at Jun. 30, 2021	17,668,409	1,707,605
Beginning balance at Mar. 31, 2021	$ 2	$ 0	104,591	39,757	3,961	66,936	215,247
Beginning balance (in shares) at Mar. 31, 2021	17,239,967	1,769,272
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 0	$ 0	0	6,567	0	767	7,334
Foreign currency translation adjustment	0	0	0	0	1,970	1,030	3,000
Exercise of stock options	$ 0	$ 0	820	0	0	0	820
Exercise of stock options (in shares)	124,094	0
Stock-based compensation	$ 0	$ 0	1,335	0	0	0	1,335
Conversion of class B common stock to Class A common stock	$ 0	$ 0	0	0	0	0	0
Conversion of class B common stock to Class A common stock (in shares)	61,667	(61,667)
Exercise of stock warrants	$ 0	$ 0	1,820	0	0	0	1,820
Exercise of stock warrants (in shares)	242,681	0
Ending balance at Jun. 30, 2021	$ 2	$ 0	$ 108,566	$ 46,324	$ 5,931	$ 68,733	$ 229,556
Ending balance (in shares) at Jun. 30, 2021	17,668,409	1,707,605

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net income	$ 13,156	$ 2,459
Adjustments to reconcile net income from operations to net cash used in operating activities
Depreciation and amortization	1,031	441
Loss on disposals of property, plant and equipment	0	1
Equity income in net income of affiliates	(615)	(357)
Unrealized gain on trading securities	(2,736)	0
Deferred income taxes	(3,502)	(507)
Stock-based compensation	2,545	1,544
Change in fair value of financial liability	0	5,431
Net changes in operating assets and liabilities:
Accounts receivable	(14,279)	(28,474)
Other receivables	(610)	(3,271)
Inventory	(47,432)	(5,630)
Prepaid expenses	(3,001)	(1,176)
Other long-term assets	(2,939)	(836)
Accounts payable	31,200	14,954
Advances from customers	25,912	(283)
Income tax payable	452	(1,419)
Other payables and accrued expenses	2,270	3,537
Deferred revenue	2,348	474
Other long-term liabilities	(3,559)	2,461
Net cash provided by (used in) operating activities	241	(10,651)
Cash flows from investing activities:
Purchase of property and equipment	(2,353)	(1,529)
Purchase of intangible assets	(431)	(55)
Prepayment for land-use-right and property	0	(15,438)
Purchase of long-term investments	0	(14,130)
Net cash used in investing activities	(2,784)	(31,152)
Cash flows from financing activities:
Proceeds from short-term borrowings	17,653	25,807
Repayments of short-term borrowings	(21,753)	(13,563)
Proceeds from long-term borrowings	1,548	0
Repayments of long-term borrowings	(794)	0
Repayments of notes payable	0	(1,820)
Proceeds from stock option exercise to common stock	2,197	873
Proceeds from warrant exercise to common stock	1,820	0
Net cash provided by financing activities	671	11,297
Effect of exchange rate changes on cash, cash equivalents and restricted cash	315	(956)
Net decrease in cash, cash equivalents and restricted cash	(1,557)	(31,462)
Cash, cash equivalents and restricted cash at beginning of period	71,766	117,859
Cash, cash equivalents and restricted cash at end of period	70,209	86,397
Supplemental disclosure of cash flow information:
Interest paid, net of capitalized interest	383	339
Cash paid for income taxes	463	4,104
Reconciliation of cash, cash equivalents and restricted cash in condensed consolidated statements of cash flows:
Cash and cash equivalents	70,209	86,397
Restricted cash	0	0
Non-cash used in financing activities:
Warrant conversion to common stock	0	399
Share cancellation	0	9,715
Cashless exercise of stock options	$ 118	$ 0

DESCRIPTION OF BUSINESS

6 Months Ended

Jun. 30, 2021

DESCRIPTION OF BUSINESS [Abstract]

DESCRIPTION OF BUSINESS

NOTE 1 – DESCRIPTION OF BUSINESS

ACM Research, Inc. (“ACM”) and its subsidiaries (collectively with ACM, the “Company”) develop, manufacture and sell wet cleaning and other equipment used to improve the manufacturing process and yield for advanced integrated chips. The Company markets and sells its wet-cleaning equipment under the brand name “Ultra C,” based on the Company’s proprietary Space Alternated Phase Shift (“SAPS”), Timely Energized Bubble Oscillation (“TEBO”), and Tahoe technologies. These tools are designed to remove random defects from a wafer surface efficiently, without damaging the wafer or its features, even at increasingly advanced process nodes.

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 (the “PRC”), 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 the PRC, 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 August 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. Based on its electro-chemical plating (“ECP”) technology, in 2019 the Company introduced 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. The Company also offers a range of custom-made equipment, including cleaners, coaters and developers, to back-end wafer assembly and packaging factories, principally in the PRC.

In 2011 ACM Shanghai formed a wholly owned subsidiary in the PRC, ACM Research (Wuxi), Inc. (“ACM Wuxi”), to manage sales and service operations.

In November 2016 ACM redomesticated 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 June 2017 ACM formed a wholly owned subsidiary in Hong Kong, CleanChip Technologies Limited (“CleanChip”), to act on the Company’s behalf in Asian markets outside the PRC by, for example, serving as a trading partner between ACM Shanghai and its customers, procuring raw materials and components, performing sales and marketing activities, and making strategic investments.

In August 2017 ACM purchased 18.77% of ACM Shanghai’s equity interests held by Shanghai Science and Technology Venture Capital Co., Ltd. On November 8, 2017, ACM purchased the remaining 18.36% of ACM Shanghai’s equity interest held by third parties, Shanghai Pudong High-Tech Investment Co., Ltd. (“PDHTI”) and Shanghai Zhangjiang Science & Technology Venture Capital Co., Ltd. (“ZSTVC”). At December 31, 2017, ACM owned all of the outstanding equity interests of ACM Shanghai, and indirectly through ACM Shanghai, owned all of the outstanding equity interests of ACM Wuxi.

On September 13, 2017, ACM effectuated a 1-for-3 reverse stock split of Class A and Class B common stock. Unless otherwise indicated, all share numbers, per share amount, share prices, exercise prices and conversion rates set forth in these notes and the accompanying consolidated financial statements have been adjusted retrospectively to reflect the reverse stock split.

On November 2, 2017, the Registration Statement on Form S-1 (File No. 333- 220451) for ACM’s initial public offering of Class A common stock was declared effective by the U.S. Securities and Exchange Commission. Shares of Class A common stock began trading on the Nasdaq Global Market on November 3, 2017, and the closing for the offering was held on November 7, 2017.

In December 2017 ACM formed a wholly owned subsidiary in the Republic of Korea, ACM Research Korea CO., LTD. (“ACM Korea”), to serve customers based in Republic of Korea and perform sales, marketing, research and development activities for new products and solutions.

In March 2019 ACM Shanghai formed a wholly owned subsidiary in the PRC, Shengwei Research (Shanghai), Inc. (“ACM Shengwei”), to manage activities related to addition of future long-term production capacity.

In April 2019 CleanChip formed a wholly owned subsidiary in California, ACM Research (CA), Inc. (“ACM California”), to provide procurement services on behalf of ACM Shanghai.

In June 2019 ACM announced plans to complete, over the following three years, a listing (the “STAR Listing”) of shares of ACM Shanghai on the Shanghai Stock Exchange’s new Sci-Tech innovAtion boaRd, known as the STAR Market, and a concurrent initial public offering (the “STAR IPO”) of ACM Shanghai shares in the PRC. ACM Shanghai is currently ACM’s primary operating subsidiary, and at the time of announcement, was wholly owned by ACM. To meet a STAR Listing requirement that it have multiple independent stockholders in the PRC, ACM Shanghai completed private placements of its shares in June and November 2019, following which, as of September 30, 2020, the private placement investors held a total of 8.3% of the outstanding shares of ACM Shanghai and ACM Research held the remaining 91.7%. As part of the STAR Listing process, in June 2020 the ownership interests held by the private investors were reclassified from redeemable non-controlling interests to non-controlling interests as the redemption feature was terminated (note 19).

In preparation for the STAR IPO, ACM completed a reorganization in December 2019 that included the sale of all of the shares of CleanChip by ACM to ACM Shanghai for $3,500. The reorganization and sale had no impact on ACM’s consolidated financial statements.

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

		Effective interest held as at
Name of subsidiaries	Place and date of incorporation	June 30, 2021			December 31, 2020
ACM Research (Shanghai), Inc.	PRC, May 2005		91.7	%		91.7	%
ACM Research (Wuxi), Inc.	PRC, July 2011		91.7	%		91.7	%
CleanChip Technologies Limited	Hong Kong, June 2017		91.7	%		91.7	%
ACM Research Korea CO., LTD.	Korea, December 2017		91.7	%		91.7	%
Shengwei Research (Shanghai), Inc.	PRC, March 2019		91.7	%		91.7	%
ACM Research (CA), Inc.	USA, April 2019		91.7	%		91.7	%
ACM Research (Cayman), Inc.	Cayman Islands, April 2019		100.0	%		100.0	%

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

6 Months Ended

Jun. 30, 2021

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

NOTE 2 – 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, including ACM Shanghai and its subsidiaries, which include ACM Wuxi, ACM Shengwei and CleanChip (the subsidiaries of which include ACM California and ACM Korea). 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 accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and the rules and regulations of the Securities and Exchange Commission 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, 2020 included in ACM’s Annual Report on Form 10-K for the year ended December 31, 2020.

The accompanying condensed consolidated balance sheet as of June 30, 2021, condensed consolidated statements of operations and comprehensive income for the three and six months ended June 30, 2021 and 2020, condensed consolidated statements of changes in stockholders’ equity for the three and six months ended June 30, 2021 and 2020, and condensed consolidated statements of cash flows for the six months ended June 30, 2021 and 2020 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 June 30, 2021 and the results of operations for the three and six months ended June 30, 2021 are not necessarily indicative of the results to be expected for any future period.

COVID-19 Assessment

The outbreak of COVID-19, the coronavirus, has grown both in the United States and globally, and related government and private sector responsive actions have adversely affected the Company’s business operations. In December 2019 a series of emergency quarantine measures taken by the PRC government disrupted domestic business activities during the weeks after the initial outbreak of COVID-19. Since that time, an increasing number of countries, including the United States, have imposed restrictions on travel to and from the PRC and elsewhere, as well as general movement restrictions, business closures and other measures imposed to slow the spread of COVID-19 and its variants. The situation continues to develop, and it is impossible to predict the effect and ultimate impact of the COVID-19 outbreak on the Company’s business operations and results. While the quarantine, social distancing and other regulatory measures instituted or recommended in response to COVID-19 are expected to be temporary, the duration of the business disruptions and related financial impact cannot be estimated at this time. The COVID-19 outbreak has been declared a worldwide health pandemic that could adversely affect the economies and financial markets of many countries, resulting in an economic downturn and changes in global economic policy that could reduce demand for the Company’s products and its customers’ chips and have a material adverse impact on the Company’s business, operating results and financial condition. Through June 30, 2021 the Company had not experienced a significant negative impact of COVID-19 on its operations, capital and financial resources, including overall liquidity position. The Company continues to monitor the impact of the COVID-19 pandemic on all aspects of its business.

The Company conducts substantially all of its product development, manufacturing, support and services in the PRC, and those activities have been directly impacted by the COVID-19 outbreak and related restrictions on transportation and public appearances. In February 2020 ACM Shanghai’s headquarters were closed for an additional six days beyond the normal Lunar New Year Holiday in accordance with Shanghai government restrictions related to the outbreak. The Company cannot assure that further closures or reductions of its PRC operations or production may not be necessary in upcoming months as the result of business interruptions arising from protective measures being taken by the PRC and other governmental agencies or of other consequences of the COVID-19 outbreak.

The Company’s corporate headquarters are located in Alameda County in the San Francisco Bay Area of California. In order to attempt to mitigate the COVID-19 pandemic, in March 2020 (a) the State of California declared a state of emergency related to the spread of COVID-19, (b) the San Francisco Department of Public Health announced aggressive recommendations to reduce the spread of the virus, (c) the health officers of six San Francisco Bay Area counties, including Alameda County, issued shelter-in-place orders, which (i) direct all individuals living in those counties to shelter at their places of residence (subject to limited exceptions), (ii) direct all businesses and governmental agencies to cease non-essential operations at physical locations in those counties, (iii) prohibit all non-essential gatherings of any number of individuals, (iv) order cessation of all non-essential travel, and (d) the Governor of California and the State Public Health Officer and Director of the California Department of Public Health ordered all individuals living in the State of California to stay at their place of residence for an indefinite period of time (subject to limited exceptions). The effects of these types of actions in the future may negatively impact productivity, disrupt the business of the Company and delay timelines, the magnitude of which will depend, in part, on the length and severity of the restrictions and other limitations on the Company’s ability to conduct its business in the ordinary course.

The prolonged and broad-based shift to a remote working environment continues to create inherent productivity, connectivity, and oversight challenges and could affect our ability to enhance, develop and support existing products and services, detect and prevent spam and problematic content, hold product sales and marketing events, and generate new sales leads, among others. In addition, the changed environment under which the Company is operating could have an effect on its internal controls over financial reporting as well as the Company’s ability to meet a number of its compliance requirements in a timely or quality manner. Additional and/or extended, governmental lockdowns, restrictions or new regulations could significantly impact the ability of our employees and vendors to work productively. Governmental restrictions have been globally inconsistent and it remains unclear when a return to worksite locations or travel will be permitted or what restrictions will be in place in those environments. As the Company continues to return its workforce in more office locations in 2021, it may experience increased costs as it prepares its facilities for a safe return to work environment and experiment with hybrid work models, in addition to potential effects on its ability to compete effectively and maintain its corporate culture.

Extended periods of interruption to the Company’s corporate, development or manufacturing facilities due to the COVID-19 outbreak could cause the Company to lose revenue and market share, which would depress its financial performance and could be difficult to recapture. The Company’s business may also be harmed if travel to or from the PRC or the United States continues to be restricted or inadvisable or if members of management and other employees are absent because they contract the coronavirus, they elect not to come to work due to the illness affecting others in the Company’s office or laboratory facilities, or they are subject to quarantines or other governmentally imposed restrictions.

Use of Estimates

The preparation of the 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 consolidated financial statements and accompanying notes. The Company’s significant accounting estimates and assumptions include, but are not limited to, those used for the valuation and recognition of fair value of trading securities, stock-based compensation arrangements and warrant liability, realization of deferred tax assets, assessment for impairment of long-lived assets, allowance for doubtful accounts, inventory valuation for excess and obsolete inventories, lower of cost and market value or net realizable value of inventories, depreciable lives of property and equipment and useful life of intangible assets.

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

Basic and Diluted Net Income per Common Share

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

	Three Months Ended June 30,					Six Months Ended June 30,
	2021		2020			2021		2020
Numerator:
Net income	$	7,334	$	496		$	13,156	$	2,459
Less: Net income attributable to non-controlling interests and redeemable non-controlling interests		767		577			1,119		835
Net income (loss) available to common stockholders, basic and diluted	$	6,567	$	(81	)	$	12,037	$	1,624

Weighted average shares outstanding, basic		19,123,659		18,050,841			18,956,195		18,085,602
Effect of dilutive securities		2,684,085		3,465,334			2,723,333		3,111,601
Weighted average shares outstanding, diluted		21,807,744		21,516,175			21,679,528		21,197,203

Net income (loss) per common share:
Basic	$	0.34	$	(0.00	)	$	0.63	$	0.09
Diluted	$	0.30	$	(0.00	)	$	0.56	$	0.08

ACM 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 did not declare any dividends during the three and six months ended June 30, 2021 and 2020, the net income per common share 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 operations and comprehensive income and in the above computation of net income per common share.

Diluted net income per common share reflects the potential dilution from securities, including stock options and issued warrants, that could share in ACM’s earnings. Certain potential dilutive securities were excluded from the net income per share calculation because the impact would be anti-dilutive. ACM’s potential dilutive securities consist of warrants and stock options for the three and six months ended June 30, 2021 and 2020.

Concentration of Credit Risk

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

The Company is potentially subject to concentrations of credit risks in its accounts receivable. For the six months ended June 30, 2021 and 2020, the Company’s three largest customers accounted for 67.1% and 92.4%, respectively, of revenue. For the three months ended June 30, 2021 and 2020, the Company’s three largest customers accounted for 81.2% and 91.0%, respectively, of revenue. As of June 30, 2021 and December 31, 2020, the Company’s three largest customers accounted for 67.1% and 75.8%, 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.

Recent Accounting Pronouncements

Recently Adopted Accounting Pronouncements

In December 2019, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. ASU 2019-12 simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. It also improves consistent application of and simplifies GAAP for other areas of Topic 740 by clarifying and amending existing guidance. The Company adopted ASU 2019-12 on January 1, 2021. The adoption of ASU 2019-12 did not have a material impact on the Company’s condensed consolidated financial statements.

In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. ASU 2020-04 provide optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform. The Company adopted ASU 2020-04 on January 1, 2021. The adoption of ASU 2020-04 did not have a material impact on the Company’s condensed consolidated financial statements.

Recent Accounting Pronouncements Not Yet Adopted

In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. ASU 2016-13 replaced the pre-existing incurred loss impairment methodology with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. ASU 2016-13 requires use of a forward-looking expected credit loss model for accounts receivables, loans and other financial instruments. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, with early adoption permitted.

In October 2019, the FASB issued ASU 2019-10, Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815) and Leases (Topic 842), which defers the effective date for public filers that are considered small reporting companies (“SRC”) as defined by the U.S. Securities and Exchange Commission (“SEC”) to fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. Since the Company was eligible to be an SRC based on its SRC determination as of November 15, 2019 (which is the issuance date of ASU 2019-10) in accordance with SEC regulations, the Company will adopt the standards for the year beginning January 1, 2023. Adoption of the standard requires using a modified retrospective approach through a cumulative-effect adjustment to retained earnings as of the effective date to align existing credit loss methodology with the new standard. The Company is evaluating the impact of this standard on its consolidated financial statements, including accounting policies, processes and systems and expects the standard will have a minor impact on its consolidated financial statements.

REVENUE FROM CONTRACTS WITH CUSTOMERS

6 Months Ended

Jun. 30, 2021

REVENUE FROM CONTRACTS WITH CUSTOMERS [Abstract]

REVENUE FROM CONTRACTS WITH CUSTOMERS

NOTE 3 – 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 related businesses. The following tables present disaggregated revenue information:

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Single Wafer Cleaning, Tahoe and Semi-Critical Cleaning Equipment	$	45,461	$	33,340	$	77,874	$	56,124
ECP (front-end and packaging), Furnace and Other Technologies		-		4,490		5,550		4,490
Advanced Packaging (excluding ECP), Services & Spares		8,403		1,219		14,172		2,783
Total Revenue By Product Category	$	53,864	$	39,049	$	97,596	$	63,397

Wet cleaning and other front-end processing tools	$	45,974	$	37,830	$	77,874	$	60,614
Advanced packaging, other processing tools, services and spares		7,890		1,219		19,722		2,783
Total Revenue Front-end and Back-End	$	53,864	$	39,049	$	97,596	$	63,397

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Mainland China	$	53,736	$	39,004	$	97,432	$	63,293
Other Regions		128		45		164		104
	$	53,864	$	39,049	$	97,596	$	63,397

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI http://asc.fasb.org/topic&trid=49130388

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130551-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130556-203045

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130550-203045

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130558-203045

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

+ Details

ACCOUNTS RECEIVABLE

6 Months Ended

Jun. 30, 2021

ACCOUNTS RECEIVABLE [Abstract]

ACCOUNTS RECEIVABLE

NOTE 4 – ACCOUNTS RECEIVABLE

At June 30, 2021 and December 31, 2020 accounts receivable consisted of the following:

	June 30, 2021		December 31, 2020
Accounts receivable	$	71,357	$	56,441
Less: Allowance for doubtful accounts		-		-
Total	$	71,357	$	56,441

The Company reviews accounts receivable on a periodic basis and makes general and specific allowances when there is doubt as to the collectability of individual balances. No allowance for doubtful accounts was considered necessary at June 30, 2021 and December 31, 2020.

INVENTORIES

6 Months Ended

Jun. 30, 2021

INVENTORIES [Abstract]

INVENTORIES

NOTE 5 – INVENTORIES

At June 30, 2021 and December 31, 2020 inventory consisted of the following:

	June 30, 2021		December 31, 2020
Raw materials	$	48,801	$	32,391
Work in process		24,084		23,871
Finished goods		63,967		32,377
Total inventory	$	136,852	$	88,639

At June 30, 2021 and December 31, 2020, the Company held an inventory reserve of $1,118 and $1,140, respectively. System shipments of first-tools to an existing or prospective customer, for which ownership does not transfer until customer acceptance, are classified as finished goods inventory and carried at cost until ownership is transferred.

PROPERTY, PLANT AND EQUIPMENT, NET

6 Months Ended

Jun. 30, 2021

PROPERTY, PLANT AND EQUIPMENT, NET [Abstract]

PROPERTY, PLANT AND EQUIPMENT, NET

NOTE 6 – PROPERTY, PLANT AND EQUIPMENT, NET

At June 30, 2021 and December 31, 2020, property, plant and equipment consisted of the following:

	June 30, 2021			December 31, 2020
Manufacturing equipment	$	6,333		$	5,966
Office equipment		1,425			1,047
Transportation equipment		216			216
Leasehold improvement		2,724			2,398
Total cost		10,698			9,627
Less: Total accumulated depreciation		(4,681	)		(3,745	)
Construction in progress		2,968			2,310
Total property, plant and equipment, net	$	8,985		$	8,192

Depreciation expense was $467 and $189 for the three months ended June 30, 2021 and 2020, respectively, and $906 and $374 for the six months ended June 30, 2021 and 2020, respectively.

LAND USE RIGHT, NET

6 Months Ended

Jun. 30, 2021

LAND USE RIGHT, NET [Abstract]

LAND USE RIGHT, NET

NOTE 7 – LAND USE RIGHT, NET

A summary of land use right is as follows:

	June 30, 2021			December 31, 2020
Land use right purchase amount	$	9,839		$	9,744
Less: Accumulated amortization		(197	)		(98	)
Land use right, net	$	9,642		$	9,646

In 2020 ACM Shanghai, through its wholly owned subsidiary ACM Shengwei, entered into an agreement for a 50-year land use right in the Lingang region of Shanghai. In July 2020 ACM Shengwei began a multi-year construction project for a new 1,000,000 square foot development and production center that will incorporate new manufacturing systems and automation technologies, and will provide floor space to support significantly increase production capacity and related research and development activities.

Amortization expense was $49 for the three months ended June 30, 2021, and $98 for the six months ended June 30, 2021.

The annual amortization of land use right for each of the five succeeding years is as follows:

Year ending December 31,
2021	$	197
2022		197
2023		197
2024		197
2025		197

OTHER LONG-TERM ASSETS

6 Months Ended

Jun. 30, 2021

OTHER LONG-TERM ASSETS [Abstract]

OTHER LONG-TERM ASSETS

NOTE 8 – OTHER LONG-TERM ASSETS

At June 30, 2021 and December 31, 2020, other long-term assets consisted of the following:

	June 30, 2021		December 31, 2020
Prepayment for property - Lingang	$	40,372	$	39,450
Prepayment for property, plant and equipment and other non-current assets		1,463		-
Prepayment for property - lease deposit		610		-
Security deposit for land use right		763		756
Others		226		290
Total other long-term assets	$	43,434	$	40,496

The prepayment for property - Lingang is for the housing in Lingang, Shanghai, which consists of (1) the contractual amount to acquire the property and (2) capitalized interest charges on the long-term loan related to acquisition of the property, which amounted to $541 as of June 30, 2021. The property is pledged for a long-term loan from China Merchants Bank (note 12).

SHORT-TERM BORROWINGS

6 Months Ended

Jun. 30, 2021

SHORT-TERM BORROWINGS [Abstract]

SHORT-TERM BORROWINGS

NOTE 9 – SHORT-TERM BORROWINGS

At June 30, 2021 and December 31, 2020, short-term and long-term borrowings consisted of the following:

	June 30, 2021		December 31, 2020
Line of credit up to RMB 80,000 from China Everbright Bank,
1)due on April 1, 2021 with an annual interest rate of 4.70%. *1 and fully repaid on March 23, 2021.		-		4,599
2)due on June 27, 2021 with an annual interest rate of 4.25%. *1 and fully repaid on June 28, 2021.		-		1,380
3)due on April 29, 2021 with an annual interest rate of 2.80%. *1 and fully repaid on March 23, 2021.		-		820
4)due on June 27, 2021 with an annual interest rate of 2.70%. *1 and fully repaid on June 25, 2021.		-		2,080
5)due on September 30, 2021 with an annual interest rate of 2.50%. *1		2,854		-
Line of credit up to RMB 20,000 from Bank of Communications,
1)due on April 12, 2021 with an annual interest rate of 4.65% and fully repaid on April 12, 2021.		-		1,533
2)due on May 24, 2021 with an annual interest rate of 3.65% and fully repaid on May 24, 2021.		-		1,533
Line of credit up to RMB 70,000 from Bank of Shanghai Pudong Branch,
1)due on May 27, 2021 with an annual interest rate of 4.68%. *2 and fully repaid on May 27, 2021.		-		2,575
2)due on June 27, 2021 with an annual interest rate of 4.68%. *2 and fully repaid on March 29, 2021.		-		1,380
3)due on May 28, 2021 with an annual interest rate of 3.48%. *2 and fully repaid on May 28, 2021.		-		2,442
4)due on June 7, 2021 with an annual interest rate of 3.50%. *2 and fully repaid on June 7, 2021.		-		1,521
5)due on June 16, 2021 with an annual interest rate of 3.50%. *2 and fully repaid on June 16, 2021.		-		1,838
Line of credit up to RMB 80,000 from China Merchants Bank,
1)due on August 10, 2021 with annual interest rate of 3.85%.		1,393		1,380
2)due on August 25, 2021 with annual interest rate of 3.85%.		3,096		3,066
3)due on February 1, 2022 with annual interest rate of 3.85%.		1,393		-
4)due on May 26, 2022 with annual interest rate of 3.9%.		1,393		-
5)due on February 2, 2022 with annual interest rate of 3.95%.		1,471		-
6)due on February 2, 2022 with annual interest rate of 3.95%.		1,471		-
7)due on February 2, 2022 with annual interest rate of 3.95%.		1,393		-
Line of credit up to RMB 100,000 from Bank of Shanghai Pudong Branch,
1)due on June 7, 2022 with an annual interest rate of 2.7%. *3.		4,618		-
Line of credit up to RMB 40,000 from Bank of China,
1)due on June 15, 2022 with an annual interest rate of 3.86%.		3,080		-

Total	$	22,162	$	26,147

*1 Guaranteed by ACM’s Chief Executive Officer

*2 Guaranteed by ACM’s Chief Executive Officer and CleanChip

*3 Guaranteed by CleanChip

For the three months ended June 30, 2021 and 2020, interest expense related to short-term borrowings amounted to $191 and $228, respectively, and $380 and $339 for the six months ended June 30, 2021 and 2020.

OTHER PAYABLE AND ACCRUED EXPENSES

6 Months Ended

Jun. 30, 2021

OTHER PAYABLE AND ACCRUED EXPENSES [Abstract]

OTHER PAYABLE AND ACCRUED EXPENSES

NOTE 10 – OTHER PAYABLE AND ACCRUED EXPENSES

At June 30, 2021 and December 31, 2020, other payable and accrued expenses consisted of the following:

	June 30, 2021		December 31, 2020
Accrued commissions		9,426		7,127
Accrued warranty		4,471		3,975
Accrued payroll		2,659		3,068
Accrued professional fees		53		384
Accrued machine testing fees		1,758		1,595
Others		3,504		2,656
Total	$	21,871	$	18,805

LEASES

6 Months Ended

Jun. 30, 2021

LEASES [Abstract]

LEASES

NOTE 11 – LEASES

The Company leases space under non-cancelable operating leases for several office 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 exercise of lease renewal options is typically at the Company’s sole discretion; therefore, the majority of renewals to extend the lease terms are not included in the Company’s right-of-use assets and lease liabilities as they are not reasonably certain of exercise. 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.

As most of the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at the lease commencement date in determining the present value of the lease payments. The Company has a centrally managed treasury function; therefore, based on the applicable lease terms and the current economic environment, it applies a portfolio approach for determining the incremental borrowing rate.

The components of lease expense were as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Operating lease cost	$	660	$	378	$	1,175	$	755
Short-term lease cost		74		47		153		97
Lease cost	$	734	$	425	$	1,328	$	852

Supplemental cash flow information related to operating leases was as follows for the three months ended June 30, 2021 and 2020:

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash outflow from operating leases	$	734	$	425	$	1,328	$	852

Maturities of lease liabilities for all operating leases were as follows as of June 30, 2021:

	December 31,
2021		1,274
2022		2,312
2023		1,027
2024		918
2025		20
Total lease payments		5,551
Less: Interest		(342	)
Present value of lease liabilities	$	5,209

The weighted average remaining lease terms and discount rates for all operating leases were as follows as of June 30, 2021 and December 31, 2020:

	June 30, 2021			December 31, 2020
Remaining lease term and discount rate:
Weighted average remaining lease term (years)		1.80			2.11
Weighted average discount rate		4.59	%		5.14	%

LONG-TERM BORROWINGS

6 Months Ended

Jun. 30, 2021

LONG-TERM BORROWINGS [Abstract]

LONG-TERM BORROWINGS

NOTE 12 – LONG-TERM BORROWINGS

At June 30, 2021 and December 31, 2020, long-term borrowings consisted of the following:

	June 30, 2021			December 31, 2020
Loan from China Merchants Bank	$	18,968		$	19,570
Loan from Bank of China	$	1,548			-
Less: Current portion		(1,799	)		(1,591	)
	$	18,717		$	17,979

The loan from China Merchants Bank is for the purpose of purchasing property in Lingang, Shanghai. The loan is repayable in 120 installments with the last installment due in November 2030, with an annual interest rate of 4.65%. The loan is pledged by the property of ACM Shengwei and guaranteed by ACM Shanghai. As of June 30, 2021, the right certificate of the pledged property has not been obtained and the procedures of the formal pledge registration in the bank had not been completed.

The loan from Bank of China is for the purpose of funding ACM Shanghai project expenditures. The loan bears interest at an annual rate of 2.6% and is repayable in 6 installments, with the last installment due in June 2024.

Scheduled principal payments for the outstanding long-term loan as of June 30, 2021 are as follows:

Year ending December 31, 2021
2021	$	890
2022		1,837
2023		1,917
2024		3,007
2025 and onwards		12,865
	$	20,516

For the three months ended June 30, 2021, interest related to long-term borrowings of $227 was incurred, of which $3 was charged to interest expenses and $224 was capitalized as other long-term assets. For the six months ended June 30, 2021, interest related to long-term borrowings of $544 was incurred, of which $3 was charged to interest expenses and $541 was capitalized as other long-term assets.

OTHER LONG-TERM LIABILITIES

6 Months Ended

Jun. 30, 2021

OTHER LONG-TERM LIABILITIES [Abstract]

OTHER LONG-TERM LIABILITIES

NOTE 13 – OTHER LONG-TERM LIABILITIES

Other long-term liabilities represent government subsidies received from PRC governmental authorities for development and commercialization of certain technology but not yet recognized. As of June 30, 2021 and December 31, 2020, other long-term liabilities consisted of the following unearned government subsidies:

	June 30, 2021		December 31, 2020
Subsidies to Stress Free Polishing project, commenced in 2008 and 2017	$	1,260	$	1,266
Subsidies to Electro Copper Plating project, commenced in 2014		1,922		2,156
Subsidies to Polytetrafluoroethylene, commenced in 2018		-		130
Subsidies to Tahoe-Single Bench Clean, commenced in 2020		600		1,544
Subsidies to Backside Clean-YMTC National Project, commenced in 2020		370		2,591
Other		405		347
Total	$	4,557	$	8,034

LONG TERM INVESTMENT

6 Months Ended

Jun. 30, 2021

LONG TERM INVESTMENT [Abstract]

LONG TERM INVESTMENT

NOTE 14 – LONG-TERM INVESTMENT

On September 6, 2017, ACM and Ninebell Co., Ltd. (“Ninebell”), a Korean company that is one of the Company’s principal material suppliers, entered into an ordinary share purchase agreement, effective as of September 11, 2017, pursuant to which Ninebell issued to ACM ordinary shares representing 20% of Ninebell’s post-closing equity for a purchase price of $1,200, and a common stock purchase agreement, effective as of September 11, 2017, pursuant to which ACM issued 133,334 shares of Class A common stock to Ninebell for a purchase price of $1,000 at $7.50 per share. The investment in Ninebell is accounted for under the equity method.

On June 27, 2019, ACM Shanghai and Shengyi Semiconductor Technology Co., Ltd. (“Shengyi”), a company based in Wuxi, China that is one of the Company’s component suppliers, entered into an agreement pursuant to which Shengyi issued to ACM Shanghai shares representing 15% of Shengyi’s post-closing equity for a purchase price of $109. The investment in Shengyi is accounted for under the equity method.

On September 5, 2019, ACM Shanghai, entered into a Partnership Agreement with six other investors, as limited partners, and Beijing Shixi Qingliu Investment Co., Ltd., as general partner and manager, with respect to the formation of Hefei Shixi Chanheng Integrated Circuit Industry Venture Capital Fund Partnership (LP), a Chinese limited partnership based in Hefei, China. Pursuant to such Partnership Agreement, on September 30, 2019, ACM Shanghai invested RMB 30,000 ($4,200), which represented 10% of the partnership’s total subscribed capital. The investment in Hefei Shixi Chanheng Integrated Circuit Industry Venture Capital Fund Partnership (LP) is accounted for under the equity method in accordance with ASC 323-30-S99-1.

The Company treats the equity investment in the consolidated financial statements under the equity method. Under the equity method, the investment is initially recorded at cost, adjusted for any excess of the Company’s share of the incorporated-date fair values of the investee’s identifiable net assets over the cost of the investment (if any). Thereafter, the investment is adjusted for the post incorporation change in the Company’s share of the investee’s net assets and any impairment loss relating to the investment.

	June 30, 2021		December 31, 2020
Ninebell	$	2,271	$	1,666
Shengyi		192		134
Hefei Shixi		4,543		4,540
Total	$	7,006	$	6,340

The Company’s share of equity investees’ net income was $295 and $209, for the three months ended June 30, 2021 and 2020, respectively, and $615 and $357 for the six-months ended June 30, 2021 and 2020, respectively, which amounts were included in equity income in net income of affiliates in the accompanying condensed consolidated statements of operations and comprehensive income.

FINANCIAL LIABILITY CARRIED AT FAIR VALUE

6 Months Ended

Jun. 30, 2021

FINANCIAL LIABILITY CARRIED AT FAIR VALUE [Abstract]

FINANCIAL LIABILITY CARRIED AT FAIR VALUE

NOTE 15 – FINANCIAL LIABILITY CARRIED AT FAIR VALUE

In December 2016 Shengxin (Shanghai) Management Consulting Limited Partnership (“SMC”) paid 20,123,500 RMB ($2,981 as of the date of funding) (the “SMC Investment”) to ACM Shanghai as an investment pursuant to terms to be subsequently negotiated. SMC is a PRC limited partnership partially owned by employees of ACM Shanghai.

In March 2017 (a) ACM issued to SMC a warrant (the “2017 Warrant”) exercisable to purchase 397,502 shares of Class A common stock at a price of $7.50 per share, for a total exercise price of $2,981, and (b) ACM Shanghai agreed to repay the SMC Investment within 60 days after the exercise of the 2017 Warrant. In March 2018 SMC exercised the 2017 Warrant in full, as a result of which (1) ACM issued 397,502 shares of Class A common stock to SMC (the “2017 Warrant Shares”), (2) SMC borrowed the funds to pay the 2017 Warrant exercise price pursuant to a senior secured promissory note (the “SMC Note”) in the principal amount of $2,981 issued to ACM Shanghai, which in turn issued to ACM a promissory note (the “Intercompany Note”) in the principal amount of $2,981 in payment of the 2017 Warrant exercise price. Each of the SMC Note and the Intercompany Note bore interest at a rate of 3.01% per annum and matured on August 17, 2023. The SMC Note was secured by a pledge of the 2017 Warrant Shares.

In connection with its follow-on public offering of Class A common stock in August 2019, ACM agreed to purchase a total of 154,821 of the 2017 Warrant Shares from SMC at a per share price of $13.195, of which (a) $1,161 was applied to reduce SMC’s obligations to ACM Shanghai under the SMC Note, and which ACM then withheld for its own account and applied to reduce ACM Shanghai’s obligations to ACM under the Intercompany Note, and (b) the remaining $882 was paid to SMC. In a separate transaction, ACM Shanghai repaid $1,161 of the SMC Investment in cash, which reduced the amount of the SMC Investment due to SMC to $1,820.

The SMC Note and SMC Investment were offsetting items in the Company’s consolidated balance sheet in accordance with ASC 210-20-45-1 up to April 30, 2020.

In preparation for the STAR IPO, ACM Shanghai was required to terminate its financial relationship with SMC. In order to facilitate such termination, on April 30, 2020, ACM entered into two agreements relating to outstanding obligations among ACM Research, ACM Shanghai and SMC. Pursuant to such agreements: (i) ACM Shanghai assigned to ACM its rights under the SMC Note, including the right to receive payment of the $1,820 payable thereunder; (ii) ACM cancelled the outstanding $1,820 obligation of ACM Shanghai under the Intercompany Note; (iii) SMC surrendered its remaining 242,681 2017 Warrant Shares to ACM Research; and (iv) in exchange for such 242,681 2017 Warrant Shares, ACM agreed to deliver to SMC certain consideration (“SMC Consideration”) agreed upon by ACM Research and SMC, subject to obtaining certain PRC regulatory approvals. Under the agreements, if the required approvals were not obtained by December 31, 2023, ACM would cancel the SMC Note as consideration for the 242,681 2017 Warrant Shares. In a separate transaction in April 2020, ACM Shanghai repaid the remaining $1,820 of the SMC Investment in cash.

Beginning April 30, 2020, the SMC Consideration was accounted for as a financial liability, and the Company applied the fair value measurement option to value the SMC Consideration in accordance with ASC 825-10-15-4a. On April 30, 2020, the SMC Consideration was $9,715, which reflected cancellation of the 2017 Warrant Shares and was recorded in equity. The financial liability was remeasured to fair value as of the end of each subsequent reporting period.

On July 29, 2020, ACM and SMC entered into an amended agreement under which, in settlement of the SMC Consideration, ACM issued to SMC a warrant (the “2020 Warrant”) to purchase 242,681 shares of Class A common stock at a purchase price of $7.50 per share, and ACM cancelled the SMC Note. The financial liability was remeasured to fair value of $21,679 as of July 29, 2020, and was retired with the issuance of the 2020 Warrant. The Company recognized a change in fair value of financial liability of $11,964 for the year ended December 31, 2020, which was reflected in the consolidated statement of operations. The Company recorded the difference of $19,859 between the 2020 Warrant of $21,679 and the SMC Note of $1,820 into equity.

The 2020 Warrant was initially measured at fair value at the issuance date and classified as equity permanently in accordance with ASC 815. The fair value of the 2020 Warrant amounted to $21,679, based on the grant date using the Black-Scholes valuation model with the following assumptions:

	July 29, 2020
Fair value of common share(1)	$	89.28
Expected term in years(2)		3.42
Volatility(3)		47.42	%
Risk-free interest rate(4)		0.15	%
Expected dividend(5)		0	%

(1)	Fair value of Class A common stock was the closing market price of the Class A common stock on July 29, 2020.

(2)	Expected term of share options was based on the average of the vesting period and the contractual term for each grant according to Staff Accounting Bulletin 110.

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

(4)	Risk-free interest rate was 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 was assumed to be 0%, as ACM had no history or expectation of paying a dividend on its common stock.

On June 9, 2021, subsequent to its obtaining the necessary PRC approvals, SMC exercised the 2020 Warrant by paying the $1,820 exercise price to ACM and surrendering the 2020 Warrant to ACM. In return, ACM delivered 242,681 shares of ACM Class A common stock to SMC.

- Definition

The entire disclosure for the financial liability for fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

TRADING SECURITIES

6 Months Ended

Jun. 30, 2021

TRADING SECURITIES [Abstract]

TRADING SECURITIES

NOTE 16 – TRADING SECURITIES

Pursuant to a Partnership Agreement dated June 9, 2020 (the “Partnership Agreement”) and a Supplementary Agreement thereto dated June 15, 2020 (the “Supplementary Agreement”), ACM Shanghai became a limited partner of Qingdao Fortune-Tech Xinxing Capital Partnership (L.P.), a Chinese limited partnership based in Shanghai, China (the “Partnership”) of which China Fortune-Tech Capital Co., Ltd serves as general partner and thirteen unaffiliated entities serve, with ACM Shanghai, as limited partners. The Partnership was formed to establish a special fund that would purchase, in a strategic placement, shares of Semiconductor Manufacturing International Corporation, (“SMIC”) to be listed on the STAR Market. SMIC is a Shanghai-based foundry that has been a customer of the Company’s single-wafer wet-cleaning tools. The limited partners of the Partnership contributed to the fund a total of RMB 2.224 billion ($315,000), of which ACM Shanghai contributed RMB 100 million ($14.2 million), or 4.3% of the total contribution, on June 18, 2020.

Upon the closing of the SMIC offering in July 2020, the initial number of SMIC shares owned by the Partnership was apportioned to all of the limited partners in proportion to their respective capital contributions (4.3% in the case of ACM Shanghai). All of the SMIC shares acquired by the Partnership are subject, under applicable Chinese laws, to lock-up restrictions that prevent sales of the shares for one year after the shares were acquired. Thereafter an individual limited partner will be able to instruct the general partner to sell, on behalf of the limited partner, all or a portion of the limited partner’s apportioned shares, subject to compliance with all laws, regulations, trading rules, the Partnership Agreement and the Supplementary Agreement. Alternatively, following the lock-up period, limited partners holding at least thirty percent of the total SMIC shares held by the Partnership will be able, pursuant to a call auction in accordance with the Supplementary Agreement, to cause the general partner to arrange to sell all of the shares desired to be offered by each of the limited partners that complies with procedural requirements provided in the Supplementary Agreement.

As SMIC was listed on the STAR Market in July 2020, ACM Shanghai’s investment is accounted for as trading securities and is stated at fair market value, which is classified as Level 2 of the hierarchy established under ASC 820 with valuations based on quoted prices for identical securities in active markets, less a discount applied to reflect the remaining lock-up period.

The components of trading securities were as follows:

	June 30, 2021		December 31, 2020
Trading securities listed in Shanghai Stock Exchange
Cost	$	15,167	$	15,020

Market value	$	31,257	$	28,239

Unrealized gain on trading securities, net of exchange difference amounted to $3,783 for the three months ended June 30, 2021, and $2,736 for the six months ended June 30, 2021.

RELATED PARTY BALANCES AND TRANSACTIONS

6 Months Ended

Jun. 30, 2021

RELATED PARTY BALANCES AND TRANSACTIONS

NOTE 17 – RELATED PARTY BALANCES AND TRANSACTIONS

Prepaid expenses		June 30, 2021				December 31, 2020
Ninebell		$	1,732			$	1,607

Accounts payable	June 30, 2021		December 31, 2020
Ninebell	$	5,331	$	2,898
Shengyi		594		1,195
Total	$	5,925	$	4,093

	Three Months Ended June 30,				Six Months Ended June 30,
Purchase of materials	2021		2020		2021		2020
Ninebell	$	7,496	$	3,370	$	14,378	$	5,523
Shengyi		287		456		645		514
Total	$	7,783	$	3,826	$	15,023	$	6,037

	Three Months Ended June 30,				Six Months Ended June 30,
Service fee charged by	2021		2020		2021		2020
Shengyi	$	117	$	144	$	259	$	190
Ninebell		-		-		-		-
Total	$	117	$	144	$	259	$	190

COMMON STOCK	6 Months Ended
COMMON STOCK	Jun. 30, 2021
COMMON STOCK [Abstract]
COMMON STOCK	NOTE 18 – COMMON STOCK ACM is authorized to issue 50,000,000 shares of Class A common stock and 2,409,738 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 unless the Board of Directors declares different dividends to the Class A common stock and Class B common stock by getting approval from a majority of common stockholders. During the three months ended June 30, 2021, ACM issued 124,094 shares of Class A common stock upon option exercises by employees and non-employees, and an additional 61,667 shares of Class A common stock upon conversion of an equal number of shares of Class B common stock. During the six months ended June 30, 2021, ACM issued 434,034 shares of Class A common stock upon option exercises by employees and non-employees, and an additional 95,001 shares of Class A common stock upon conversion of an equal number of shares of Class B common stock. During the three and six months ended June 30, 2021, ACM issued 242,681 shares of Class A common stock upon the warrant exercise by SMC (Note 15). During the three months ended June 30, 2020, ACM issued 115,425 shares of Class A common stock upon option exercises by employees and non-employees, and an additional 60,002 shares of Class A common stock upon conversion of an equal number of shares of Class B common stock. During the six months ended June 30, 2020, ACM issued 185,903 shares of Class A common stock upon option exercises by employees and non-employees, and an additional 60,002 shares of Class A common stock upon conversion of an equal number of shares of Class B common stock. During the six months ended June 30, 2020, ACM issued 64,717 shares of Class A common stock upon a cashless warrant exercise by a non-employee. During the three and six months ended June 30, 2020, SMC transferred its ownership of 242,681 shares of Class A common stock to ACM in exchange for the SMC Consideration. The 242,681 shares were cancelled during the three and six months ended June 30, 2020. (Note 15) At June 30, 2021 and December 31, 2020, the number of shares of Class A common stock issued and outstanding was 17,668,409, and 16,896,693, respectively. At June 30, 2021 and December 31, 2020, the number of shares of Class B common stock issued and outstanding was 1,707,605 and 1,802,606, respectively.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496171-112644

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496171-112644

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496189-112644

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-URI http://asc.fasb.org/topic&trid=2208762

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496189-112644

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496171-112644

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496189-112644

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 16
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496180-112644

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e)(1))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

REDEEMABLE NON-CONTROLLING INTERESTS

6 Months Ended

Jun. 30, 2021

REDEEMABLE NON-CONTROLLING INTERESTS [Abstract]

REDEEMABLE NON-CONTROLLING INTERESTS

NOTE 19 – REDEEMABLE NON-CONTROLLING INTERESTS

During the second quarter of 2020, the redemption feature of the private placement funding terminated and the aggregate proceeds of the funding therefore were reclassified from redeemable non-controlling interests to non-controlling interests. At June 30, 2020, the balance of redeemable non-controlling interest was nil.

The components of the change in the redeemable non-controlling interests for the six months ended June 30, 2020 are presented in the following table:

Balance at December 31, 2019	$	60,162
Net income attributable to redeemable non-controlling interests		643
Effect of foreign currency translation gain attributable to redeemable non-controlling interests		(847	)
Reclassification of redeemable non-controlling interest		(59,958	)
Balance at June 30, 2020	$	-

STOCK-BASED COMPENSATION

6 Months Ended

Jun. 30, 2021

STOCK-BASED COMPENSATION [Abstract]

STOCK-BASED COMPENSATION

NOTE 20 – STOCK-BASED COMPENSATION

In January 2020 ACM Shanghai adopted a 2019 Stock Option Incentive Plan (the “Subsidiary Stock Option Plan”) that provides for, among other incentives, the granting to officers, directors, employees of options to purchase shares of ACM Shanghai’s common stock. The fair value of the stock options granted is estimated at the date of grant based on the Black-Scholes option pricing model using assumptions generally consistent with those used for ACM’s stock options. Because ACM Shanghai shares are not publicly traded, the expected volatility is estimated with reference to the average historical volatility of a group of publicly traded companies that are believed to have similar characteristics to ACM Shanghai.

ACM’s stock-based compensation consists of employee and non-employee awards issued under its 1998 Stock Option Plan, its 2016 Omnibus Incentive Plan, and as standalone options. ACM granted stock options to employees under the 2016 Omnibus Incentive Plan during the three and six months ended June 30, 2021. The vesting condition may consist of a service period 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 service period based condition is estimated at the date of grant using the Black-Scholes option pricing model. The fair value of the stock options granted with market based condition is estimated at the date of grant using the Monte Carlo simulation model.

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Stock-Based Compensation Expense:
Cost of revenue	$	110	$	43	$	181	$	88
Sales and marketing expense		478		164		983		258
Research and development expense		279		188		508		375
General and administrative expense		468		460		873		823
	$	1,335	$	855	$	2,545	$	1,544

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Stock-based compensation expense by type:
Employee stock purchase plan	$	1,217	$	635	$	2,302	$	1,066
Non-employee stock purchase plan		30		140		70		312
Subsidiary option grants		88		80		173		166
	$	1,335	$	855	$	2,545	$	1,544

The following table summarizes the Company’s employee share option activities during the six months ended June 30, 2021:

	Number of Option Share	Weighted Average Grant Date Fair Value		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
Outstanding at December 31, 2020	3,191,411	$	5.13	$	12.73	7.13 years
Granted	106,400		50.67		111.98
Exercised	(336,216)		2.27		5.74
Forfeited/cancelled	(19,212)		30.33		69.14
Outstanding at June 30, 2021	2,942,383	$	6.94	$	16.75	6.99 years
Vested and exercisable at June 30, 2021	1,845,023

As of June 30, 2021 and December 31, 2020, $11,033 and $8,733, respectively, of total unrecognized employee stock-based compensation expense, net of estimated forfeitures, related to stock-based awards for ACM were expected to be recognized over a weighted-average period of 1.82 years and 1.89 years, respectively. Total recognized compensation cost may be adjusted for future changes in estimated forfeitures.

The fair value of options granted to employee with a service period based condition is estimated on the grant date using the Black-Scholes valuation.

	Six Months Ended
	June 30, 2021
Fair value of common share(1)	$	111.98
Expected term in years(2)		5.50-6.25
Volatility(3)		48.53	%
Risk-free interest rate(4)		1.00	%
Expected dividend(5)		0	%

(1)	Equal to closing value 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 according to Staff Accounting Bulletin 110.

(3)	Volatility is calculated based on the historical volatility of ACM’s comparable companies 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 six-months ended June 30, 2021:

	Number of Option Shares	Weighted Average Grant Date Fair Value		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
Outstanding at December 31, 2020	836,038	$	1.02	$	3.07	4.92 years
Granted	-		-		-
Exercised	(97,818)		1.03		3.91
Expired	-		-		-
Forfeited/cancelled	(250)		0.30		0.75
Outstanding at June 30, 2021	737,970	$	1.02	$	2.96	4.43 years
Vested and exercisable at June 30, 2021	724,220

As of June 30, 2021 and December 31, 2020, $125 and $195, 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 0.07 years and 0.09 years, respectively. Total recognized compensation cost may be adjusted for future changes in estimated forfeitures.

ACM Shanghai Option Grants

The following table summarizes the ACM Shanghai employee stock option activities during the three months ended June 30, 2021:

	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, 2020	5,423,654	$	0.23	$	1.89	_3.50 years
Granted	-		-		-
Exercised	-		-		-
Expired	-		-		-
Forfeited/cancelled	(46,154)		0.24		2.01
Outstanding at June 30, 2021	5,377,500	$	0.24	$	2.01	3.01 years
Vested and exercisable at June 30, 2021	-

As of June 30, 2021 and December 31, 2020, $693 and $822, 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 2.01 years and 2.5 years, respectively. Total recognized compensation cost may be adjusted for future changes in estimated forfeitures.

INCOME TAXES

6 Months Ended

Jun. 30, 2021

INCOME TAXES [Abstract]

INCOME TAXES

NOTE 21 – 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. 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 12.5% to 25% for Chinese income tax purposes due to the effects of the valuation allowance and certain permanent differences from book-tax differences. As a result, the Company recorded income tax benefit (expense) of $2,755 and $(2,163) during the six months ended June 30, 2021 and 2020, respectively.

As of June 30, 2021, the Company’s total unrecognized tax benefits were $570 of which $422 would affect the effective tax rate if recognized. The Company will recognize interest and penalties, when they occur, related to uncertain tax provisions as a component of tax expense. No interest or penalties were recognized for the six months ended June 30, 2021.

The Company files income tax returns in the United States and state and foreign jurisdictions. The federal, state and foreign income tax returns are under the statute of limitations subject to tax examinations for the tax years ended December 31, 2002 through December 31, 2020. To the extent the Company has tax attribute carry-forwards, the tax years in which the attribute was generated may still be adjusted upon examination by the U.S. Internal Revenue Service, state or foreign tax authorities to the extent utilized in a future period.

The Company’s effective tax rate differs from statutory rates of 21% for U.S. federal income tax purposes and 12.5% to 25% for Chinese income tax purposes due to the effects of the valuation allowance and certain permanent differences as it pertains to book-tax differences in the treatment of stock-based compensation and non-US research expenses. The Company’s three PRC subsidiaries, ACM Shanghai, ACM Wuxi and ACM Shengwei, are liable for PRC corporate income taxes at the rates of 12.5%, 25% and 25%, respectively. Pursuant to the Corporate Income Tax Law of the PRC, ACM’s PRC subsidiaries generally would be liable for PRC 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 and 2018, with an effective period of three years. In 2021, ACM Shanghai was certified as an eligible integrated circuit production enterprise and is entitled to a preferential income tax rate of 12.5% from January 1, 2020 to December 31, 2022.

ACM files income tax returns in the United States and state and foreign jurisdictions. Those federal, state and foreign income tax returns are under the statute of limitations subject to tax examinations for 2009 through 2020. To the extent ACM has tax attribute carryforwards, the tax years in which the attribute was generated may still be adjusted upon examination by the U.S. Internal Revenue Service or state or foreign tax authorities to the extent utilized in a future period.

In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which enhances and simplifies various aspects of the income tax accounting guidance, including requirements such as the elimination of exceptions related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period, the recognition of deferred tax liabilities for outside basis differences, ownership changes in investments, and tax basis step-up in goodwill obtained in a transaction that is not a business combination. The guidance is effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. The impact of the adoption by the Company on its condensed consolidated financial statements and disclosures is immaterial.

Income tax benefit (expense) was as follows:

	Three Months Ended June 30,						Six Months Ended June 30,
	2021			2020			2021		2020
Total income tax benefit (expense)	$	(15	)	$	(1,859	)	$	2,755	$	(2,163	)

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32809-109319

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 270
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6424409&loc=d3e44925-109338

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

COMMITMENTS AND CONTINGENCIES	6 Months Ended
COMMITMENTS AND CONTINGENCIES	Jun. 30, 2021
COMMITMENTS AND CONTINGENCIES [Abstract]
COMMITMENTS AND CONTINGENCIES	NOTE 22 – COMMITMENTS AND CONTINGENCIES The Company leases offices under non-cancelable operating lease agreements. See note 8 for future minimum lease payments under non-cancelable operating lease agreements with initial terms of one year or more. As of June 30, 2021, the Company had $2,942 of open capital commitments. Covenants in ACM Shengwei’s Grant Contract for State-owned Construction Land Use Right in Shanghai City with the China (Shanghai) Pilot Free Trade Zone Lingang Special Area Administration require, among other things, that ACM Shengwei 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 ($63,400) 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 the PRC 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 June 30, 2021, the Company had paid in total $10,328 for its Lingang-related investments. 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 unascertainable damages. The Company’s management has evaluated all such proceedings and claims that existed as of June 30, 2021 and December 31, 2020. In the opinion of management, no provision for liability nor disclosure was required as of June 30, 2021 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 June 30, 2021, the Company had one outstanding legal proceeding. On December 21, 2020, a putative class action lawsuit against ACM and three of its officers was filed in the U.S. District Court for the Northern District of California under the caption Kain v. ACM Research, Inc., et al., No. 3:20-cv-09241. The complaint alleges claims under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder, and seeks monetary damages in an unspecified amount as well as costs and expenses incurred in the litigation. On April 15, 2021, the court appointed Mr. Kain as lead plaintiff, finding that no better-suited candidates emerged during the statutory sixty-day period following public notice of the lawsuit. On May 27, 2021, defendants filed a motion to dismiss Mr. Kain’s complaint. Defendants’ motion to dismiss is fully briefed and currently scheduled to be heard by the court on September 9, 2021. ACM’s management believes the claims are without merit and intends to vigorously defend this litigation. The Company is currently unable to predict the outcome of this lawsuit and therefore cannot determine the likelihood of loss or estimate a range of possible loss.

SUBSEQUENT EVENT	6 Months Ended
SUBSEQUENT EVENT	Jun. 30, 2021
SUBSEQUENT EVENT [Abstract]
SUBSEQUENT EVENT	NOTE 23 – SUBSEQUENT EVENT On July 13, 2021, the Company filed a certificate of amendment to our restated certificate of incorporation with the Secretary of State of the State of Delaware. The amendment i) increased the authorized number of shares of Class A common stock from 50,000,000 to 150,000,000 with 60,000,000 of the 100,000,000 additional authorized shares of Class A common stock reserved for issuance only as dividends on outstanding shares of Class A common stock; ii) increased the authorized number of shares of Class B common stock from 2,409,738 to 5,307,816, with all of the authorized but unissued shares of Class B common stock being available for issuance only as dividends on outstanding shares of Class B common stock; and iii) removed a now-obsolete provision related to the automatic conversion of Class B common stock into Class A common stock.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

6 Months Ended

Jun. 30, 2021

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]

Basis of Presentation and Principles of Consolidation

COVID-19 Assessment

Use of Estimates

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

Basic and Diluted Net Income per Common Share

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

	Three Months Ended June 30,					Six Months Ended June 30,
	2021		2020			2021		2020
Numerator:
Net income	$	7,334	$	496		$	13,156	$	2,459
Less: Net income attributable to non-controlling interests and redeemable non-controlling interests		767		577			1,119		835
Net income (loss) available to common stockholders, basic and diluted	$	6,567	$	(81	)	$	12,037	$	1,624

Weighted average shares outstanding, basic		19,123,659		18,050,841			18,956,195		18,085,602
Effect of dilutive securities		2,684,085		3,465,334			2,723,333		3,111,601
Weighted average shares outstanding, diluted		21,807,744		21,516,175			21,679,528		21,197,203

Net income (loss) per common share:
Basic	$	0.34	$	(0.00	)	$	0.63	$	0.09
Diluted	$	0.30	$	(0.00	)	$	0.56	$	0.08

Concentration of Credit Risk

Recent Accounting Pronouncements

Recently Adopted Accounting Pronouncements

Recent Accounting Pronouncements Not Yet Adopted

DESCRIPTION OF BUSINESS (Tables)

6 Months Ended

Jun. 30, 2021

DESCRIPTION OF BUSINESS [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	June 30, 2021			December 31, 2020
ACM Research (Shanghai), Inc.	PRC, May 2005		91.7	%		91.7	%
ACM Research (Wuxi), Inc.	PRC, July 2011		91.7	%		91.7	%
CleanChip Technologies Limited	Hong Kong, June 2017		91.7	%		91.7	%
ACM Research Korea CO., LTD.	Korea, December 2017		91.7	%		91.7	%
Shengwei Research (Shanghai), Inc.	PRC, March 2019		91.7	%		91.7	%
ACM Research (CA), Inc.	USA, April 2019		91.7	%		91.7	%
ACM Research (Cayman), Inc.	Cayman Islands, April 2019		100.0	%		100.0	%

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

6 Months Ended

Jun. 30, 2021

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]

Basic and Diluted Net Income per Common Share

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

	Three Months Ended June 30,					Six Months Ended June 30,
	2021		2020			2021		2020
Numerator:
Net income	$	7,334	$	496		$	13,156	$	2,459
Less: Net income attributable to non-controlling interests and redeemable non-controlling interests		767		577			1,119		835
Net income (loss) available to common stockholders, basic and diluted	$	6,567	$	(81	)	$	12,037	$	1,624

Weighted average shares outstanding, basic		19,123,659		18,050,841			18,956,195		18,085,602
Effect of dilutive securities		2,684,085		3,465,334			2,723,333		3,111,601
Weighted average shares outstanding, diluted		21,807,744		21,516,175			21,679,528		21,197,203

Net income (loss) per common share:
Basic	$	0.34	$	(0.00	)	$	0.63	$	0.09
Diluted	$	0.30	$	(0.00	)	$	0.56	$	0.08

REVENUE FROM CONTRACTS WITH CUSTOMERS (Tables)

6 Months Ended

Jun. 30, 2021

REVENUE FROM CONTRACTS WITH CUSTOMERS [Abstract]

Disaggregated Revenue Information

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Single Wafer Cleaning, Tahoe and Semi-Critical Cleaning Equipment	$	45,461	$	33,340	$	77,874	$	56,124
ECP (front-end and packaging), Furnace and Other Technologies		-		4,490		5,550		4,490
Advanced Packaging (excluding ECP), Services & Spares		8,403		1,219		14,172		2,783
Total Revenue By Product Category	$	53,864	$	39,049	$	97,596	$	63,397

Wet cleaning and other front-end processing tools	$	45,974	$	37,830	$	77,874	$	60,614
Advanced packaging, other processing tools, services and spares		7,890		1,219		19,722		2,783
Total Revenue Front-end and Back-End	$	53,864	$	39,049	$	97,596	$	63,397

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Mainland China	$	53,736	$	39,004	$	97,432	$	63,293
Other Regions		128		45		164		104
	$	53,864	$	39,049	$	97,596	$	63,397

ACCOUNTS RECEIVABLE (Tables)

6 Months Ended

Jun. 30, 2021

ACCOUNTS RECEIVABLE [Abstract]

Accounts Receivable

At June 30, 2021 and December 31, 2020 accounts receivable consisted of the following:

	June 30, 2021		December 31, 2020
Accounts receivable	$	71,357	$	56,441
Less: Allowance for doubtful accounts		-		-
Total	$	71,357	$	56,441

INVENTORIES (Tables)

6 Months Ended

Jun. 30, 2021

INVENTORIES [Abstract]

Inventory

At June 30, 2021 and December 31, 2020 inventory consisted of the following:

	June 30, 2021		December 31, 2020
Raw materials	$	48,801	$	32,391
Work in process		24,084		23,871
Finished goods		63,967		32,377
Total inventory	$	136,852	$	88,639

PROPERTY, PLANT AND EQUIPMENT, NET (Tables)

6 Months Ended

Jun. 30, 2021

PROPERTY, PLANT AND EQUIPMENT, NET [Abstract]

Property, Plant and Equipment

At June 30, 2021 and December 31, 2020, property, plant and equipment consisted of the following:

	June 30, 2021			December 31, 2020
Manufacturing equipment	$	6,333		$	5,966
Office equipment		1,425			1,047
Transportation equipment		216			216
Leasehold improvement		2,724			2,398
Total cost		10,698			9,627
Less: Total accumulated depreciation		(4,681	)		(3,745	)
Construction in progress		2,968			2,310
Total property, plant and equipment, net	$	8,985		$	8,192

LAND USE RIGHT, NET (Tables)

6 Months Ended

Jun. 30, 2021

LAND USE RIGHT, NET [Abstract]

Land Use Rights

A summary of land use right is as follows:

	June 30, 2021			December 31, 2020
Land use right purchase amount	$	9,839		$	9,744
Less: Accumulated amortization		(197	)		(98	)
Land use right, net	$	9,642		$	9,646

Annual Amortization of Land Use Right

The annual amortization of land use right for each of the five succeeding years is as follows:

Year ending December 31,
2021	$	197
2022		197
2023		197
2024		197
2025		197

OTHER LONG-TERM ASSETS (Tables)

6 Months Ended

Jun. 30, 2021

OTHER LONG-TERM ASSETS [Abstract]

Other Long-term Assets

At June 30, 2021 and December 31, 2020, other long-term assets consisted of the following:

	June 30, 2021		December 31, 2020
Prepayment for property - Lingang	$	40,372	$	39,450
Prepayment for property, plant and equipment and other non-current assets		1,463		-
Prepayment for property - lease deposit		610		-
Security deposit for land use right		763		756
Others		226		290
Total other long-term assets	$	43,434	$	40,496

SHORT-TERM BORROWINGS (Tables)

6 Months Ended

Jun. 30, 2021

SHORT-TERM BORROWINGS [Abstract]

Short-Term Borrowings

At June 30, 2021 and December 31, 2020, short-term and long-term borrowings consisted of the following:

	June 30, 2021		December 31, 2020
Line of credit up to RMB 80,000 from China Everbright Bank,
1)due on April 1, 2021 with an annual interest rate of 4.70%. *1 and fully repaid on March 23, 2021.		-		4,599
2)due on June 27, 2021 with an annual interest rate of 4.25%. *1 and fully repaid on June 28, 2021.		-		1,380
3)due on April 29, 2021 with an annual interest rate of 2.80%. *1 and fully repaid on March 23, 2021.		-		820
4)due on June 27, 2021 with an annual interest rate of 2.70%. *1 and fully repaid on June 25, 2021.		-		2,080
5)due on September 30, 2021 with an annual interest rate of 2.50%. *1		2,854		-
Line of credit up to RMB 20,000 from Bank of Communications,
1)due on April 12, 2021 with an annual interest rate of 4.65% and fully repaid on April 12, 2021.		-		1,533
2)due on May 24, 2021 with an annual interest rate of 3.65% and fully repaid on May 24, 2021.		-		1,533
Line of credit up to RMB 70,000 from Bank of Shanghai Pudong Branch,
1)due on May 27, 2021 with an annual interest rate of 4.68%. *2 and fully repaid on May 27, 2021.		-		2,575
2)due on June 27, 2021 with an annual interest rate of 4.68%. *2 and fully repaid on March 29, 2021.		-		1,380
3)due on May 28, 2021 with an annual interest rate of 3.48%. *2 and fully repaid on May 28, 2021.		-		2,442
4)due on June 7, 2021 with an annual interest rate of 3.50%. *2 and fully repaid on June 7, 2021.		-		1,521
5)due on June 16, 2021 with an annual interest rate of 3.50%. *2 and fully repaid on June 16, 2021.		-		1,838
Line of credit up to RMB 80,000 from China Merchants Bank,
1)due on August 10, 2021 with annual interest rate of 3.85%.		1,393		1,380
2)due on August 25, 2021 with annual interest rate of 3.85%.		3,096		3,066
3)due on February 1, 2022 with annual interest rate of 3.85%.		1,393		-
4)due on May 26, 2022 with annual interest rate of 3.9%.		1,393		-
5)due on February 2, 2022 with annual interest rate of 3.95%.		1,471		-
6)due on February 2, 2022 with annual interest rate of 3.95%.		1,471		-
7)due on February 2, 2022 with annual interest rate of 3.95%.		1,393		-
Line of credit up to RMB 100,000 from Bank of Shanghai Pudong Branch,
1)due on June 7, 2022 with an annual interest rate of 2.7%. *3.		4,618		-
Line of credit up to RMB 40,000 from Bank of China,
1)due on June 15, 2022 with an annual interest rate of 3.86%.		3,080		-

Total	$	22,162	$	26,147

*1 Guaranteed by ACM’s Chief Executive Officer

*2 Guaranteed by ACM’s Chief Executive Officer and CleanChip

*3 Guaranteed by CleanChip

OTHER PAYABLE AND ACCRUED EXPENSES (Tables)

6 Months Ended

Jun. 30, 2021

OTHER PAYABLE AND ACCRUED EXPENSES [Abstract]

Other Payable and Accrued Expenses

At June 30, 2021 and December 31, 2020, other payable and accrued expenses consisted of the following:

	June 30, 2021		December 31, 2020
Accrued commissions		9,426		7,127
Accrued warranty		4,471		3,975
Accrued payroll		2,659		3,068
Accrued professional fees		53		384
Accrued machine testing fees		1,758		1,595
Others		3,504		2,656
Total	$	21,871	$	18,805

LEASES (Tables)

6 Months Ended

Jun. 30, 2021

LEASES [Abstract]

Components of Lease Expense

The components of lease expense were as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Operating lease cost	$	660	$	378	$	1,175	$	755
Short-term lease cost		74		47		153		97
Lease cost	$	734	$	425	$	1,328	$	852

Supplemental Cash Flow Information Related to Operating Leases

Supplemental cash flow information related to operating leases was as follows for the three months ended June 30, 2021 and 2020:

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash outflow from operating leases	$	734	$	425	$	1,328	$	852

Maturities of Lease Liabilities for Operating Leases

Maturities of lease liabilities for all operating leases were as follows as of June 30, 2021:

	December 31,
2021		1,274
2022		2,312
2023		1,027
2024		918
2025		20
Total lease payments		5,551
Less: Interest		(342	)
Present value of lease liabilities	$	5,209

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 as of June 30, 2021 and December 31, 2020:

	June 30, 2021			December 31, 2020
Remaining lease term and discount rate:
Weighted average remaining lease term (years)		1.80			2.11
Weighted average discount rate		4.59	%		5.14	%

LONG-TERM BORROWINGS (Tables)

6 Months Ended

Jun. 30, 2021

LONG-TERM BORROWINGS [Abstract]

Long-Term Borrowings

At June 30, 2021 and December 31, 2020, long-term borrowings consisted of the following:

	June 30, 2021			December 31, 2020
Loan from China Merchants Bank	$	18,968		$	19,570
Loan from Bank of China	$	1,548			-
Less: Current portion		(1,799	)		(1,591	)
	$	18,717		$	17,979

Principal Payments for Outstanding Long-Term Loan

Scheduled principal payments for the outstanding long-term loan as of June 30, 2021 are as follows:

Year ending December 31, 2021
2021	$	890
2022		1,837
2023		1,917
2024		3,007
2025 and onwards		12,865
	$	20,516

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24072-122690

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=124435984&loc=d3e28541-108399

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21506-112644

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69E
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495743-112612

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21521-112644

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21538-112644

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=123599511&loc=d3e64711-112823

Reference 11: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21475-112644

+ Details

OTHER LONG-TERM LIABILITIES (Tables)

6 Months Ended

Jun. 30, 2021

OTHER LONG-TERM LIABILITIES [Abstract]

Other Long-Term Liabilities

	June 30, 2021		December 31, 2020
Subsidies to Stress Free Polishing project, commenced in 2008 and 2017	$	1,260	$	1,266
Subsidies to Electro Copper Plating project, commenced in 2014		1,922		2,156
Subsidies to Polytetrafluoroethylene, commenced in 2018		-		130
Subsidies to Tahoe-Single Bench Clean, commenced in 2020		600		1,544
Subsidies to Backside Clean-YMTC National Project, commenced in 2020		370		2,591
Other		405		347
Total	$	4,557	$	8,034

LONG TERM INVESTMENT (Tables)

6 Months Ended

Jun. 30, 2021

LONG TERM INVESTMENT [Abstract]

Components of Long-Term Investment

	June 30, 2021		December 31, 2020
Ninebell	$	2,271	$	1,666
Shengyi		192		134
Hefei Shixi		4,543		4,540
Total	$	7,006	$	6,340

FINANCIAL LIABILITY CARRIED AT FAIR VALUE (Tables)

6 Months Ended

Jun. 30, 2021

FINANCIAL LIABILITY CARRIED AT FAIR VALUE [Abstract]

Assumptions Used to Determine Fair Value of Warrants

	July 29, 2020
Fair value of common share(1)	$	89.28
Expected term in years(2)		3.42
Volatility(3)		47.42	%
Risk-free interest rate(4)		0.15	%
Expected dividend(5)		0	%

(1)	Fair value of Class A common stock was the closing market price of the Class A common stock on July 29, 2020.

(2)	Expected term of share options was based on the average of the vesting period and the contractual term for each grant according to Staff Accounting Bulletin 110.

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

(4)	Risk-free interest rate was 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 was assumed to be 0%, as ACM had no history or expectation of paying a dividend on its common stock.

TRADING SECURITIES (Tables)

6 Months Ended

Jun. 30, 2021

TRADING SECURITIES [Abstract]

Components of Trading Securities

The components of trading securities were as follows:

	June 30, 2021		December 31, 2020
Trading securities listed in Shanghai Stock Exchange
Cost	$	15,167	$	15,020

Market value	$	31,257	$	28,239

RELATED PARTY BALANCES AND TRANSACTIONS (Tables)

6 Months Ended

Jun. 30, 2021

Related Party Balances and Transactions

Prepaid expenses		June 30, 2021				December 31, 2020
Ninebell		$	1,732			$	1,607

Accounts payable	June 30, 2021		December 31, 2020
Ninebell	$	5,331	$	2,898
Shengyi		594		1,195
Total	$	5,925	$	4,093

	Three Months Ended June 30,				Six Months Ended June 30,
Purchase of materials	2021		2020		2021		2020
Ninebell	$	7,496	$	3,370	$	14,378	$	5,523
Shengyi		287		456		645		514
Total	$	7,783	$	3,826	$	15,023	$	6,037

	Three Months Ended June 30,				Six Months Ended June 30,
Service fee charged by	2021		2020		2021		2020
Shengyi	$	117	$	144	$	259	$	190
Ninebell		-		-		-		-
Total	$	117	$	144	$	259	$	190

REDEEMABLE NON-CONTROLLING INTERESTS (Tables)

6 Months Ended

Jun. 30, 2021

REDEEMABLE NON-CONTROLLING INTERESTS [Abstract]

Components of Change in Redeemable Non-controlling Interests

The components of the change in the redeemable non-controlling interests for the six months ended June 30, 2020 are presented in the following table:

Balance at December 31, 2019	$	60,162
Net income attributable to redeemable non-controlling interests		643
Effect of foreign currency translation gain attributable to redeemable non-controlling interests		(847	)
Reclassification of redeemable non-controlling interest		(59,958	)
Balance at June 30, 2020	$	-

STOCK-BASED COMPENSATION (Tables)

6 Months Ended

Jun. 30, 2021

Stock-Based Compensation [Abstract]

Components of Stock-based Compensation Expense

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Stock-Based Compensation Expense:
Cost of revenue	$	110	$	43	$	181	$	88
Sales and marketing expense		478		164		983		258
Research and development expense		279		188		508		375
General and administrative expense		468		460		873		823
	$	1,335	$	855	$	2,545	$	1,544

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Stock-based compensation expense by type:
Employee stock purchase plan	$	1,217	$	635	$	2,302	$	1,066
Non-employee stock purchase plan		30		140		70		312
Subsidiary option grants		88		80		173		166
	$	1,335	$	855	$	2,545	$	1,544

Assumptions Used to Determine Fair Value of Share Options Granted

The fair value of options granted to employee with a service period based condition is estimated on the grant date using the Black-Scholes valuation.

	Six Months Ended
	June 30, 2021
Fair value of common share(1)	$	111.98
Expected term in years(2)		5.50-6.25
Volatility(3)		48.53	%
Risk-free interest rate(4)		1.00	%
Expected dividend(5)		0	%

(1)	Equal to closing value 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 according to Staff Accounting Bulletin 110.

(3)	Volatility is calculated based on the historical volatility of ACM’s comparable companies 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.

Employee Share Option [Member]

Stock-Based Compensation [Abstract]

Summary of Share Option Activities

The following table summarizes the ACM Shanghai employee stock option activities during the three months ended June 30, 2021:

	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, 2020	5,423,654	$	0.23	$	1.89	_3.50 years
Granted	-		-		-
Exercised	-		-		-
Expired	-		-		-
Forfeited/cancelled	(46,154)		0.24		2.01
Outstanding at June 30, 2021	5,377,500	$	0.24	$	2.01	3.01 years
Vested and exercisable at June 30, 2021	-

Employee Share Option [Member] | ACM Shanghai [Member]

Stock-Based Compensation [Abstract]

Summary of Share Option Activities

The following table summarizes the Company’s employee share option activities during the six months ended June 30, 2021:

	Number of Option Share	Weighted Average Grant Date Fair Value		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
Outstanding at December 31, 2020	3,191,411	$	5.13	$	12.73	7.13 years
Granted	106,400		50.67		111.98
Exercised	(336,216)		2.27		5.74
Forfeited/cancelled	(19,212)		30.33		69.14
Outstanding at June 30, 2021	2,942,383	$	6.94	$	16.75	6.99 years
Vested and exercisable at June 30, 2021	1,845,023

Non-Employee Stock Option [Member]

Stock-Based Compensation [Abstract]

Summary of Share Option Activities

The following table summarizes the Company’s non-employee share option activities during the six-months ended June 30, 2021:

	Number of Option Shares	Weighted Average Grant Date Fair Value		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
Outstanding at December 31, 2020	836,038	$	1.02	$	3.07	4.92 years
Granted	-		-		-
Exercised	(97,818)		1.03		3.91
Expired	-		-		-
Forfeited/cancelled	(250)		0.30		0.75
Outstanding at June 30, 2021	737,970	$	1.02	$	2.96	4.43 years
Vested and exercisable at June 30, 2021	724,220

INCOME TAXES (Tables)

6 Months Ended

Jun. 30, 2021

INCOME TAXES [Abstract]

Income Tax Benefit (Expense)

Income tax benefit (expense) was as follows:

	Three Months Ended June 30,						Six Months Ended June 30,
	2021			2020			2021		2020
Total income tax benefit (expense)	$	(15	)	$	(1,859	)	$	2,755	$	(2,163	)

DESCRIPTION OF BUSINESS (Details) $ in Thousands		6 Months Ended	12 Months Ended
DESCRIPTION OF BUSINESS (Details) $ in Thousands	Sep. 13, 2017	Jun. 30, 2021	Dec. 31, 2019 USD ($)	Dec. 31, 2020	Nov. 08, 2017	Aug. 31, 2017
Class A Common Stock [Member]
Description of Business [Abstract]
Reverse stock split	0.33
Class B Common Stock [Member]
Description of Business [Abstract]
Reverse stock split	0.33
ACM Research (Shanghai), Inc. [Member]
Description of Business [Abstract]
Purchase of equity interest percentage		8.30%			18.36%	18.77%
Name of subsidiaries		ACM Research (Shanghai), Inc.
Term to complete listing of shares		3 years
Date and place of Incorporation		PRC, May 2005
Effective interest held as at		91.70%		91.70%
ACM Research (Wuxi), Inc. [Member]
Description of Business [Abstract]
Name of subsidiaries		ACM Research (Wuxi), Inc.
Date and place of Incorporation		PRC, July 2011
Effective interest held as at		91.70%		91.70%
CleanChip Technologies Limited [Member]
Description of Business [Abstract]
Proceeds from sale of interest in subsidiary			$ 3,500
Name of subsidiaries		CleanChip Technologies Limited
Date and place of Incorporation		Hong Kong, June 2017
Effective interest held as at		91.70%		91.70%
ACM Research Korea CO., LTD [Member]
Description of Business [Abstract]
Name of subsidiaries		ACM Research Korea CO., LTD.
Date and place of Incorporation		Korea, December 2017
Effective interest held as at		91.70%		91.70%
Shengwei Research (Shanghai), Inc. [Member]
Description of Business [Abstract]
Purchase of equity interest percentage			91.70%
Name of subsidiaries		Shengwei Research (Shanghai), Inc.
Date and place of Incorporation		PRC, March 2019
Effective interest held as at		91.70%		91.70%
ACM Research (CA), Inc. [Member]
Description of Business [Abstract]
Name of subsidiaries		ACM Research (CA), Inc.
Date and place of Incorporation		USA, April 2019
Effective interest held as at		91.70%		91.70%
ACM Research (Cayman), Inc. [Member]
Description of Business [Abstract]
Name of subsidiaries		ACM Research (Cayman), Inc.
Date and place of Incorporation		Cayman Islands, April 2019
Effective interest held as at		100.00%		100.00%

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, COVID-19 Assessment (Details) - County	1 Months Ended
	Mar. 31, 2020	Feb. 29, 2020
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Number of days headquarters closed		6 days
Number of San Francisco Bay Area counties	6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Basic and Diluted Net Income per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator [Abstract]
Net income	$ 7,334	$ 496	$ 13,156	$ 2,459
Less: Net income attributable to non-controlling interests and redeemable non-controlling interests	767	577	1,119	835
Net income (loss) attributable to ACM Research, Inc.	$ 6,567	$ (81)	$ 12,037	$ 1,624
Weighted average shares outstanding, basic (in shares)	19,123,659	18,050,841	18,956,195	18,085,602
Effect of dilutive securities (in shares)	2,684,085	3,465,334	2,723,333	3,111,601
Weighted average shares outstanding, diluted (in shares)	21,807,744	21,516,175	21,679,528	21,197,203
Net income (loss) per common share [Abstract]
Basic (in dollars per share)	$ 0.34	$ 0.00	$ 0.63	$ 0.09
Diluted (in dollars per share)	$ 0.30	$ 0.00	$ 0.56	$ 0.08

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Concentration of Credit Risk (Details) - Customer Concentration Risk [Member] - Three Customers [Member] - Customer	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Revenue Benchmark [Member]
Concentration of Credit Risk [Abstract]
Number of major customers	3	3	3	3
Concentration of credit risk	81.20%	91.00%	67.10%	92.40%
Accounts Receivable [Member]
Concentration of Credit Risk [Abstract]
Number of major customers			3		3
Concentration of credit risk			67.10%		75.80%

REVENUE FROM CONTRACTS WITH CUSTOMERS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregated Revenue Information [Abstract]
Revenue	$ 53,864	$ 39,049	$ 97,596	$ 63,397
Mainland China [Member]
Disaggregated Revenue Information [Abstract]
Revenue	53,736	39,004	97,432	63,293
Oher Regions [Member]
Disaggregated Revenue Information [Abstract]
Revenue	128	45	164	104
Single Wafer Cleaning, Tahoe and Semi-Critical Cleaning Equipment [Member]
Disaggregated Revenue Information [Abstract]
Revenue	45,461	33,340	77,874	56,124
ECP (Front-end and Packaging), Furnace and Other Technologies [Member]
Disaggregated Revenue Information [Abstract]
Revenue	0	4,490	5,550	4,490
Advanced Packaging (Excluding ECP), Services & Spares [Member]
Disaggregated Revenue Information [Abstract]
Revenue	8,403	1,219	14,172	2,783
Wet Cleaning and Other Front-end Processing Tools [Member]
Disaggregated Revenue Information [Abstract]
Revenue	45,974	37,830	77,874	60,614
Advanced Packaging, Other Processing Tools, Services and Spares [Member]
Disaggregated Revenue Information [Abstract]
Revenue	$ 7,890	$ 1,219	$ 19,722	$ 2,783

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8906-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9031-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9038-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130543-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130545-203045

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

ACCOUNTS RECEIVABLE (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accounts Receivable [Abstract]
Accounts receivable	$ 71,357	$ 56,441
Less: Allowance for doubtful accounts	0	0
Total	$ 71,357	$ 56,441

INVENTORIES (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Inventory [Abstract]
Raw materials	$ 48,801	$ 32,391
Work in process	24,084	23,871
Finished goods	63,967	32,377
Total inventory	136,852	88,639
Inventory reserve	$ 1,118	$ 1,140

PROPERTY, PLANT AND EQUIPMENT, NET (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Total cost	$ 10,698		$ 10,698		$ 9,627
Less: Total accumulated depreciation	(4,681)		(4,681)		(3,745)
Construction in progress	2,968		2,968		2,310
Total property, plant and equipment, net	8,985		8,985		8,192
Depreciation expense	467	$ 189	906	$ 374
Manufacturing Equipment [Member]
Property, Plant and Equipment [Abstract]
Total cost	6,333		6,333		5,966
Office Equipment [Member]
Property, Plant and Equipment [Abstract]
Total cost	1,425		1,425		1,047
Transportation Equipment [Member]
Property, Plant and Equipment [Abstract]
Total cost	216		216		216
Leasehold Improvement [Member]
Property, Plant and Equipment [Abstract]
Total cost	$ 2,724		$ 2,724		$ 2,398

LAND USE RIGHT, NET (Details) $ in Thousands	3 Months Ended	6 Months Ended
LAND USE RIGHT, NET (Details) $ in Thousands	Jun. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jul. 31, 2020 ft²
Land use Right [Abstract]
Land use right purchase amount	$ 9,839	$ 9,839	$ 9,744
Less: Accumulated amortization	(197)	(197)	(98)
Land use right, net	9,642	9,642	9,646
Amortization	$ 49	$ 98
Annual Amortization of Land use Right [Abstract]
2021			197
2022			197
2023			197
2024			197
2025			$ 197
Shangwei Research (Shanghai), Inc. [Member]
Land use Right [Abstract]
Right to use land lease term		50 years
Area for development and production center \| ft²				1,000,000

OTHER LONG-TERM ASSETS (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Other Long-term Assets [Abstract]
Prepayment for property - Lingang	$ 40,372	$ 39,450
Prepayment for property, plant and equipment and other non-current assets	1,463	0
Prepayment for property - lease deposit	610	0
Security deposit for land use right	763	756
Others	226	290
Total other long-term assets	43,434	$ 40,496
Capitalized interest charges related to property	$ 541

SHORT-TERM BORROWINGS (Details)
¥ in Thousands, $ in Thousands

3 Months Ended

6 Months Ended

Jun. 30, 2021

USD ($)

Jun. 30, 2020

USD ($)

Jun. 30, 2021

USD ($)

Jun. 30, 2020

USD ($)

Jun. 30, 2021

CNY (¥)

Dec. 31, 2020

USD ($)

Short-Term Borrowings [Abstract]

Short-term borrowings

$ 22,162

$ 26,147

Interest expense related to short-term borrowings

191

$ 228

380

$ 339

Line of Credit Due on April 1, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

^[1]

$ 0

4,599

Maximum borrowing capacity | ¥

¥ 80,000

Annual interest rate

4.70%

Line of credit due date

Mar. 23, 2021

Line of Credit Due on June 27, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

^[1]

$ 0

1,380

Maximum borrowing capacity | ¥

80,000

Annual interest rate

4.25%

Line of credit due date

Jun. 28, 2021

Line of Credit Due on April 29, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

^[1]

$ 0

820

Maximum borrowing capacity | ¥

80,000

Annual interest rate

2.80%

Line of credit due date

Mar. 23, 2021

Line of Credit Due on June 27, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

^[1]

$ 0

2,080

Maximum borrowing capacity | ¥

80,000

Annual interest rate

2.70%

Line of credit due date

Jun. 25, 2021

Line of Credit Due on September 30, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

^[1]

2,854

$ 2,854

Maximum borrowing capacity | ¥

80,000

Annual interest rate

2.50%

Line of credit due date

Sep. 30, 2021

Line of Credit Due on April 12, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

$ 0

1,533

Maximum borrowing capacity | ¥

20,000

Annual interest rate

4.65%

Line of credit due date

Apr. 12, 2021

Line of Credit Due on May 24, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

$ 0

1,533

Maximum borrowing capacity | ¥

20,000

Annual interest rate

3.65%

Line of credit due date

May 24, 2021

Line of Credit Due on May 27, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

^[2]

$ 0

2,575

Maximum borrowing capacity | ¥

70,000

Annual interest rate

4.68%

Line of credit due date

May 27, 2021

Line of Credit Due on June 27, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

^[2]

$ 0

1,380

Maximum borrowing capacity | ¥

70,000

Annual interest rate

4.68%

Line of credit due date

Mar. 29, 2021

Line of Credit Due on May 28, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

^[2]

$ 0

2,442

Maximum borrowing capacity | ¥

70,000

Annual interest rate

3.48%

Line of credit due date

May 28, 2021

Line of Credit Due on June 7, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

^[2]

$ 0

1,521

Maximum borrowing capacity | ¥

70,000

Annual interest rate

3.50%

Line of credit due date

Jun. 07, 2021

Line of Credit Due on June 16, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

^[2]

$ 0

1,838

Maximum borrowing capacity | ¥

70,000

Annual interest rate

3.50%

Line of credit due date

Jun. 16, 2021

Line of Credit Due on August 10, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

1,393

$ 1,393

1,380

Maximum borrowing capacity | ¥

80,000

Annual interest rate

3.85%

Line of credit due date

Aug. 10, 2021

Line of Credit Due on August 25, 2021 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

3,096

$ 3,096

3,066

Maximum borrowing capacity | ¥

80,000

Annual interest rate

3.85%

Line of credit due date

Aug. 25, 2021

Line of Credit Due on February 1, 2022 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

1,393

$ 1,393

Maximum borrowing capacity | ¥

80,000

Annual interest rate

3.85%

Line of credit due date

Feb. 01, 2022

Line of Credit Due on May 26, 2022 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

1,393

$ 1,393

Maximum borrowing capacity | ¥

80,000

Annual interest rate

3.90%

Line of credit due date

May 26, 2022

Line of Credit Due on February 2, 2022 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

1,471

$ 1,471

Maximum borrowing capacity | ¥

80,000

Annual interest rate

3.95%

Line of credit due date

Feb. 02, 2022

Line of Credit Due on February 2 2022 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

1,471

$ 1,471

Maximum borrowing capacity | ¥

80,000

Annual interest rate

3.95%

Line of credit due date

Feb. 02, 2022

Line of Credit Due on February 2, 2022 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

1,393

$ 1,393

Maximum borrowing capacity | ¥

80,000

Annual interest rate

3.95%

Line of credit due date

Feb. 02, 2022

Line of Credit Due on June 7, 2022 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

^[3]

4,618

$ 4,618

Maximum borrowing capacity | ¥

100,000

Annual interest rate

2.70%

Line of credit due date

Jun. 07, 2022

Line of Credit Due on June 15, 2022 [Member]

Short-Term Borrowings [Abstract]

Short-term borrowings

$ 3,080

$ 0

Maximum borrowing capacity | ¥

¥ 40,000

Annual interest rate

3.86%

Line of credit due date

Jun. 15, 2022

[1]	Guaranteed by ACM’s Chief Executive Officer
[2]	Guaranteed by ACM’s Chief Executive Officer and CleanChip
[3]	Guaranteed by CleanChip

OTHER PAYABLE AND ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
OTHER PAYABLE AND ACCRUED EXPENSES [Abstract]
Accrued commissions	$ 9,426	$ 7,127
Accrued warranty	4,471	3,975
Accrued payroll	2,659	3,068
Accrued professional fees	53	384
Accrued machine testing fees	1,758	1,595
Others	3,504	2,656
Total	$ 21,871	$ 18,805

LEASES (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
LEASES (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Components of lease expense [Abstract]
Operating lease cost	$ 660	$ 378	$ 1,175	$ 755
Short-term lease cost	74	47	153	97
Lease cost	734	425	1,328	852
Cash paid for amounts included in the measurement of lease liabilities [Abstract]
Operating cash outflow from operating leases	734	$ 425	1,328	$ 852
Maturities of lease liabilities [Abstract]
2021	1,274		1,274
2022	2,312		2,312
2023	1,027		1,027
2024	918		918
2025	20		20
Total lease payments	5,551		5,551
Less: Interest	(342)		(342)
Present value of lease liabilities	$ 5,209		$ 5,209
Weighted average remaining lease terms and discount rates [Abstract]
Weighted average remaining lease term	1 year 9 months 18 days		1 year 9 months 18 days		2 years 1 month 9 days
Weighted average discount rate	4.59%		4.59%		5.14%

LONG-TERM BORROWINGS (Details) $ in Thousands	3 Months Ended	6 Months Ended
LONG-TERM BORROWINGS (Details) $ in Thousands	Jun. 30, 2021 USD ($)	Jun. 30, 2021 USD ($) Intallment	Dec. 31, 2020 USD ($)
Long-Term Borrowings [Abstract]
Long-term debt	$ 20,516	$ 20,516
Less: Current portion	(1,799)	(1,799)	$ (1,591)
Long-term Borrowings	18,717	18,717	17,979
Principal Payments of Long-Term Loan [Abstract]
2021	890	890
2022	1,837	1,837
2023	1,917	1,917
2024	3,007	3,007
2025 and onwards	12,865	12,865
Long-term debt	20,516	20,516
Interest expense related to long-term borrowings incurred	227	544
Interest expense charged to long-term borrowings	3	3
Capitalized interest charged as other long-term assets	224	541
China Merchants Bank [Member]
Long-Term Borrowings [Abstract]
Long-term debt	18,968	$ 18,968	19,570
Number of installments for loan repayable \| Intallment		120
Last installment due date		Nov. 30, 2030
Annual interest rate		4.65%
Principal Payments of Long-Term Loan [Abstract]
Long-term debt	18,968	$ 18,968	19,570
Bank of China [Member]
Long-Term Borrowings [Abstract]
Long-term debt	1,548	$ 1,548	0
Number of installments for loan repayable \| Intallment		6
Last installment due date		Jun. 30, 2024
Annual interest rate		2.60%
Principal Payments of Long-Term Loan [Abstract]
Long-term debt	$ 1,548	$ 1,548	$ 0

OTHER LONG-TERM LIABILITIES (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Other Long-term Liabilities [Abstract]
Other long-term liabilities	$ 4,557	$ 8,034
Subsidies to Stress Free Polishing Project, Commenced in 2008 and 2017 [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	1,260	1,266
Subsidies to Electro Copper Plating Project, Commenced in 2014 [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	1,922	2,156
Subsidies to Polytetrafluoroethylene, Commenced in 2018 [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	0	130
Subsidies to Tahoe-Single Bench Clean, Commenced in 2020 [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	600	1,544
Subsidies to Backside Clean-YMTC National Project, Commenced in 2020 [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	370	2,591
Other [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	$ 405	$ 347

LONG TERM INVESTMENT (Details) $ / shares in Units, ¥ in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
	Sep. 05, 2019 shares	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2019 CNY (¥)	Jun. 27, 2019 USD ($)	Sep. 11, 2017 USD ($) $ / shares shares
Classification of Investments [Abstract]
Total		$ 7,006		$ 7,006		$ 6,340
Equity income in net income of affiliates		295	$ 209	615	$ 357
Ninebell [Member]
Investments [Abstract]
Percentage of ordinary shares issued										20.00%
Purchase price										$ 1,200
Classification of Investments [Abstract]
Total		2,271		2,271		1,666
Ninebell [Member] \| Class A Common Stock [Member]
Investments [Abstract]
Purchase price										$ 1,000
Shares issued (in shares) \| shares										133,334
Share price (in dollars per share) \| $ / shares										$ 7.50
Shengyi [Member]
Investments [Abstract]
Percentage of ordinary shares issued									15.00%
Investment - equity method									$ 109
Number of investors with agreements entered \| shares	6
Classification of Investments [Abstract]
Total		192		192		134
Hefei Shixi [Member]
Investments [Abstract]
Investment in partnership							$ 4,200	¥ 30,000
Ownership percentage in partnership							10.00%	10.00%
Classification of Investments [Abstract]
Total		$ 4,543		$ 4,543		$ 4,540

FINANCIAL LIABILITY CARRIED AT FAIR VALUE (Details)
$ / shares in Units, ¥ in Thousands, $ in Thousands

1 Months Ended

3 Months Ended

6 Months Ended

12 Months Ended

Jun. 09, 2021

USD ($)

Jul. 29, 2020

USD ($)

$ / shares

Apr. 30, 2020

USD ($)

Agreement

Aug. 31, 2019

USD ($)

$ / shares

Mar. 31, 2018

USD ($)

Mar. 31, 2017

USD ($)

$ / shares

Jun. 30, 2021

USD ($)

Jun. 30, 2020

USD ($)

Jun. 30, 2021

USD ($)

Jun. 30, 2020

USD ($)

Dec. 31, 2020

USD ($)

Dec. 31, 2016

USD ($)

Dec. 31, 2016

CNY (¥)

Change in fair value of financial liability

$ 0

$ 5,431

$ 0

$ 5,431

2020 Warrants [Member]

Financial liability carried at fair value

$ 21,679

Change in fair value of financial liability

$ 11,964

Fair value warrant amount

21,679

Fair Value of Options Granted [Abstract]

Fair value of common share (in dollars per share) | $ / shares

^[1]

$ 89.28

Expected term

^[2]

3 years 5 months 1 day

Volatility

^[3]

47.42%

Risk-free interest rate

^[4]

0.00%

Expected dividend

^[5]

0.15%

Common Class A [Member] | 2020 Warrants [Member]

Shares issued (in shares) | shares

242,681

Fair Value of Options Granted [Abstract]

Fair value of common share (in dollars per share) | $ / shares

$ 7.50

ACM Shanghai [Member]

Repayments of notes

$ 1,161

Number of agreement | Agreement

ACM Shanghai [Member] | Senior Secured Promissory Note [Member]

Receivables

$ 1,820

ACM Shanghai [Member] | Intercompany Note [Member]

Promissory note principal amount

$ 2,981

Interest rate on promissory note

3.01%

Promissory note maturity date

Aug. 17, 2023

Fair value warrant amount

$ 1,820

SMC [Member]

Payment for investment

$ 2,981

¥ 20,123,500

Shares issued value

$ 1,820

Investment repayment period

60 days

Number of shares repurchased/surrender in exchange (in shares) | shares

242,681

154,821

Repayments of notes

$ 882

Investment due amount

$ 1,820

Consideration price in fair value

$ 9,715

Issuance of warrant for settlement of financial liability

$ 19,859

Fair Value of Options Granted [Abstract]

Fair value of common share (in dollars per share) | $ / shares

$ 13.195

SMC [Member] | Senior Secured Promissory Note [Member]

Promissory note principal amount

$ 2,981

Interest rate on promissory note

3.01%

Promissory note maturity date

Aug. 17, 2023

SMC [Member] | Common Class A [Member]

Shares issued (in shares) | shares

242,681

397,502

Shares issued value

$ 2,981

Fair Value of Options Granted [Abstract]

Fair value of common share (in dollars per share) | $ / shares

$ 13.195

$ 7.50

SMC [Member] | Common Class A [Member] | Senior Secured Promissory Note [Member]

Exercise of common stock warrant issued (in shares) | shares

397,502

SMC [Member] | ACM Shanghai [Member]

Repayment of investment in cash

$ 1,820

$ 1,161

[1]	Fair value of Class A common stock was the closing market price of the Class A common stock on July 29, 2020.
[2]	Expected term of share options was based on the average of the vesting period and the contractual term for each grant according to Staff Accounting Bulletin 110.
[3]	Volatility was calculated based on the historical volatility of the stock of companies comparable to ACM in the period equal to the expected term of each grant.
[4]	Expected dividend was assumed to be 0%, as ACM had no history or expectation of paying a dividend on its common stock.
[5]	Risk-free interest rate was 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.

TRADING SECURITIES (Details) $ in Thousands, ¥ in Millions	3 Months Ended	6 Months Ended
TRADING SECURITIES (Details) $ in Thousands, ¥ in Millions	Jun. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 18, 2020 USD ($)	Jun. 18, 2020 CNY (¥)
Trading securities listed in Shanghai Stock Exchange [Abstract]
Cost	$ 15,167	$ 15,167	$ 15,020
Market value	31,257	31,257	$ 28,239
Unrealized gain on trading securities	$ 3,783	$ 2,736
Qingdao LP [Member]
Investments [Abstract]
Total capital fund of limited partnership				$ 315,000	¥ 2,224
Investment in partnership				$ 14,200	¥ 100
Ownership percentage in partnership				4.30%	4.30%
SMIC [Member] \| Minimum [Member]
Investments [Abstract]
Ownership percentage in partnership	30.00%	30.00%

RELATED PARTY BALANCES AND TRANSACTIONS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Related Party Transaction [Abstract]
Accounts payable	$ 5,925		$ 5,925		$ 4,093
Purchase of materials	7,783	$ 3,826	15,023	$ 6,037
Service fee charged by	117	144	259	190
Ninebell Co., Ltd [Member]
Related Party Transaction [Abstract]
Prepaid expenses	1,732		1,732		1,607
Accounts payable	5,331		5,331		2,898
Purchase of materials	7,496	3,370	14,378	5,523
Service fee charged by	0	0	0	0
Shengyi Semiconductor Technology Co., Ltd [Member]
Related Party Transaction [Abstract]
Accounts payable	594		594		$ 1,195
Purchase of materials	287	456	645	514
Service fee charged by	$ 117	$ 144	$ 259	$ 190

- Definition

Direct costs arising from transactions with related parties who are not affiliates or joint Ventures. These costs are categorized as cost of goods sold.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2)
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(C))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(k)(1))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(B))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

+ Details

COMMON STOCK (Details)	1 Months Ended		3 Months Ended		6 Months Ended
COMMON STOCK (Details)	Apr. 30, 2020 shares	Aug. 31, 2019 shares	Jun. 30, 2021 Vote $ / shares shares	Jun. 30, 2020 shares	Jun. 30, 2021 Vote $ / shares shares	Jun. 30, 2020 shares	Dec. 31, 2020 $ / shares shares
Class of Stock [Abstract]
Number of Shares Cancelled				242,681		242,681
SMC [Member]
Class of Stock [Abstract]
Number of shares repurchased/surrender in exchange (in shares)	242,681	154,821
Common Class A [Member]
Class of Stock [Abstract]
Common stock, shares authorized (in shares)			50,000,000		50,000,000		50,000,000
Common stock, par value (in dollars per share) \| $ / shares			$ 0.0001		$ 0.0001		$ 0.0001
Number of votes for each share entitled \| Vote			1		1
Common stock, shares issued (in shares)			17,668,409		17,668,409		16,896,693
Common stock, shares outstanding (in shares)			17,668,409		17,668,409		16,896,693
Common Class B [Member]
Class of Stock [Abstract]
Common stock, shares authorized (in shares)			2,409,738		2,409,738		2,409,738
Common stock, par value (in dollars per share) \| $ / shares			$ 0.0001		$ 0.0001		$ 0.0001
Number of votes for each share entitled \| Vote			20		20
Convertible shares in to Class A common stock (in shares)					1
Common stock, shares issued (in shares)			1,707,605		1,707,605		1,802,606
Common stock, shares outstanding (in shares)			1,707,605		1,707,605		1,802,606
Common Stock [Member] \| Common Class A [Member]
Class of Stock [Abstract]
Stock issued upon exercise of stock options (in shares)			124,094	115,425	434,034	185,903
Conversion of class B common stock to Class A common stock (in shares)			61,667	60,002	95,001	60,002
Exercise of common stock warrant issued (in shares)			242,681		242,681	64,717
Number of shares repurchased/surrender in exchange (in shares)				242,681		242,681
Common Stock [Member] \| Common Class B [Member]
Class of Stock [Abstract]
Stock issued upon exercise of stock options (in shares)			0	0	0	0
Conversion of class B common stock to Class A common stock (in shares)			(61,667)	(60,002)	(95,001)	(60,002)
Exercise of common stock warrant issued (in shares)			0		0	0
Number of shares repurchased/surrender in exchange (in shares)				0		0

REDEEMABLE NON-CONTROLLING INTERESTS (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)
REDEEMABLE NON-CONTROLLING INTERESTS [Abstract]
Redeemable non-controlling interest	$ 0	$ 0
Change in Redeemable Non-controlling Interests [Abstract]
Balance		60,162
Net income attributable to redeemable non-controlling interests		643
Effect of foreign currency translation gain attributable to redeemable non-controlling interests		(847)
Reclassification of redeemable non-controlling interest	(59,958)	(59,958)
Balance	$ 0	$ 0

STOCK-BASED COMPENSATION, Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	$ 1,335	$ 855	$ 2,545	$ 1,544
Employee Stock Purchase Plan [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	1,217	635	2,302	1,066
Employee Stock Purchase Plan [Member] \| ACM Shanghai [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	88	80	173	166
Non-Employee Stock Purchase Plan [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	30	140	70	312
Cost of Revenue [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	110	43	181	88
Sales and Marketing Expense [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	478	164	983	258
Research and Development Expense [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	279	188	508	375
General and Administrative Expense [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	$ 468	$ 460	$ 873	$ 823

STOCK-BASED COMPENSATION, Share Option Activities (Details) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares
Employee Share Option [Member]
Number of Option Share [Roll Forward]
Outstanding, beginning of period (in shares) \| shares	3,191,411
Granted (in shares) \| shares	106,400
Exercised (in shares) \| shares	(336,216)
Forfeited/cancelled (in shares) \| shares	(19,212)
Outstanding, end of period (in shares) \| shares	2,942,383	3,191,411
Vested and exercisable (in shares) \| shares	1,845,023
Weighted Average Grant Date Fair Value [Abstract]
Outstanding at beginning of period (in dollars per share)	$ 5.13
Granted (in dollars per share)	50.67
Exercised (in dollars per share)	2.27
Forfeited/cancelled (in dollars per share)	30.33
Outstanding at end of period (in dollars per share)	6.94	$ 5.13
Weighted Average Exercise Price [Abstract]
Outstanding, beginning of period (in dollars per share)	12.73
Granted (in dollars per share)	111.98
Exercised (in dollars per share)	5.74
Forfeited/cancelled (in dollars per share)	69.14
Outstanding, end of period (in dollars per share)	$ 16.75	$ 12.73
Weighed Average Remaining Contractual Term [Abstract]
Outstanding weighed average remaining contractual term	6 years 11 months 26 days	7 years 1 month 17 days
Unrecognized employee stock-based compensation expense \| $	$ 11,033	$ 8,733
Weighted-average period over which unrecognized compensation is expected to be recognized	1 year 9 months 25 days	1 year 10 months 20 days
Employee Share Option [Member] \| ACM Shanghai [Member]
Number of Option Share [Roll Forward]
Outstanding, beginning of period (in shares) \| shares	5,423,654
Granted (in shares) \| shares	0
Exercised (in shares) \| shares	0
Expired (in shares) \| shares	0
Forfeited/cancelled (in shares) \| shares	(46,154)
Outstanding, end of period (in shares) \| shares	5,377,500	5,423,654
Vested and exercisable (in shares) \| shares	0
Weighted Average Grant Date Fair Value [Abstract]
Outstanding at beginning of period (in dollars per share)	$ 0.23
Granted (in dollars per share)	0
Exercised (in dollars per share)	0
Expired (in dollars per share)	0
Forfeited/cancelled (in dollars per share)	0.24
Outstanding at end of period (in dollars per share)	0.24	$ 0.23
Weighted Average Exercise Price [Abstract]
Outstanding, beginning of period (in dollars per share)	1.89
Granted (in dollars per share)	0
Exercised (in dollars per share)	0
Expired (in dollars per share)	0
Forfeited/cancelled (in dollars per share)	2.01
Outstanding, end of period (in dollars per share)	$ 2.01	$ 1.89
Weighed Average Remaining Contractual Term [Abstract]
Outstanding weighed average remaining contractual term	3 years 3 days	3 years 6 months
Non-Employee Stock Option [Member]
Number of Option Share [Roll Forward]
Outstanding, beginning of period (in shares) \| shares	836,038
Granted (in shares) \| shares	0
Exercised (in shares) \| shares	(97,818)
Expired (in shares) \| shares	0
Forfeited/cancelled (in shares) \| shares	(250)
Outstanding, end of period (in shares) \| shares	737,970	836,038
Vested and exercisable (in shares) \| shares	724,220
Weighted Average Grant Date Fair Value [Abstract]
Outstanding at beginning of period (in dollars per share)	$ 1.02
Granted (in dollars per share)	0
Exercised (in dollars per share)	1.03
Expired (in dollars per share)	0
Forfeited/cancelled (in dollars per share)	0.30
Outstanding at end of period (in dollars per share)	1.02	$ 1.02
Weighted Average Exercise Price [Abstract]
Outstanding, beginning of period (in dollars per share)	3.07
Granted (in dollars per share)	0
Exercised (in dollars per share)	3.91
Expired (in dollars per share)	0
Forfeited/cancelled (in dollars per share)	0.75
Outstanding, end of period (in dollars per share)	$ 2.96	$ 3.07
Weighed Average Remaining Contractual Term [Abstract]
Outstanding weighed average remaining contractual term	4 years 5 months 4 days	4 years 11 months 1 day
Unrecognized employee stock-based compensation expense \| $	$ 125	$ 195
Weighted-average period over which unrecognized compensation is expected to be recognized	25 days	1 month 2 days
Non-Employee Stock Option [Member] \| ACM Shanghai [Member]
Weighed Average Remaining Contractual Term [Abstract]
Unrecognized employee stock-based compensation expense \| $	$ 693	$ 822
Weighted-average period over which unrecognized compensation is expected to be recognized	2 years 3 days	2 years 6 months

STOCK-BASED COMPENSATION, Assumptions Used to Determine Fair Value of Share Options Granted (Details) - Employee Share Option [Member] - Service Period Based [Member]

6 Months Ended

Jun. 30, 2021

$ / shares

Fair Value of Options Granted [Abstract]

Fair value of common share (in dollars per share)

$ 111.98

^[1]

Volatility

48.53%

^[2]

Risk-free interest rate

1.00%

^[3]

Expected dividend

0.00%

^[4]

Minimum [Member]

Fair Value of Options Granted [Abstract]

Expected term in years

5 years 6 months

^[5]

Maximum [Member]

Fair Value of Options Granted [Abstract]

Expected term in years

6 years 3 months

^[5]

[1]	Equal to closing value on the grant date.
[2]	Volatility is calculated based on the historical volatility of ACM’s comparable companies in the period equal to the expected term of each grant.
[3]	Risk-free interest rate was 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.
[4]	Expected dividend is assumed to be 0% as ACM has no history or expectation of paying a dividend on its common stock.
[5]	Expected term of share options is based on the average of the vesting period and the contractual term for each grant according to Staff Accounting Bulletin 110.

INCOME TAXES (Details) $ in Thousands	3 Months Ended		6 Months Ended
INCOME TAXES (Details) $ in Thousands	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) Subsidiary	Jun. 30, 2020 USD ($)
Income Taxes [Abstract]
Statutory U.S federal income tax rate			21.00%
Unrecognized tax benefits	$ 570		$ 570
Unrecognized tax benefits that would impact effective tax rate	422		422
Interest or penalties			0
Income Tax Benefit (Expense) [Abstract]
Total income tax benefit (expense)	$ (15)	$ (1,859)	$ 2,755	$ (2,163)
ACM Research (Shanghai), Inc. [Member]
Income Taxes [Abstract]
Foreign corporate tax rate			15.00%
PRC [Member]
Income Taxes [Abstract]
Number of subsidiaries \| Subsidiary			3
Foreign corporate tax rate			25.00%
Effective period of preferential income tax rate			3 years
PRC [Member] \| Minimum [Member]
Income Taxes [Abstract]
Foreign corporate tax rate			12.50%
PRC [Member] \| Maximum [Member]
Income Taxes [Abstract]
Foreign corporate tax rate			25.00%
PRC [Member] \| ACM Research (Shanghai), Inc. [Member]
Income Taxes [Abstract]
Foreign corporate tax rate			12.50%
PRC [Member] \| ACM Research (Wuxi), Inc. [Member]
Income Taxes [Abstract]
Foreign corporate tax rate			25.00%
PRC [Member] \| Shengwei Research (Shanghai), Inc. [Member]
Income Taxes [Abstract]
Foreign corporate tax rate			25.00%

COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands, ¥ in Millions	6 Months Ended
	Jun. 30, 2021 USD ($) LegalProceeding	Jun. 30, 2021 CNY (¥)	Dec. 21, 2020 ExecutiveOfficers
COMMITMENTS AND CONTINGENCIES [Abstract]
Commitments	$ 2,942
Required liquidate damage value	$ 63,400	¥ 450.0
Land use rights period	6 years	6 years
Annual total taxes	$ 22,000	¥ 157.6
Investments	$ 10,328
Number of outstanding legal proceedings \| LegalProceeding	1
Number of executive officers against lawsuit filed \| ExecutiveOfficers			3

SUBSEQUENT EVENT (Details) - shares	Jul. 13, 2021	Jun. 30, 2021	Dec. 31, 2020
Class A Common Stock [Member]
Subsequent Event [Line Items]
Common stock, shares authorized (in shares)		50,000,000	50,000,000
Additional shares reserved for issuance as dividends (in shares)		60,000,000
Common stock, additional shares authorized (in shares)		100,000,000
Class B Common Stock [Member]
Subsequent Event [Line Items]
Common stock, shares authorized (in shares)		2,409,738	2,409,738
Subsequent Event [Member] \| Class A Common Stock [Member]
Subsequent Event [Line Items]
Common stock, shares authorized (in shares)	150,000,000
Subsequent Event [Member] \| Class B Common Stock [Member]
Subsequent Event [Line Items]
Common stock, shares authorized (in shares)	5,307,816