ACM Research (ACMR) 10-Q 8 May 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	May 04, 2020
Entity Listings [Line Items]
Entity Registrant Name	ACM Research, Inc.
Entity Central Index Key	0001680062
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Entity Address, State or Province	CA
Class A Common Stock [Member]
Entity Listings [Line Items]
Entity Common Stock, Shares Outstanding		16,327,346
Class B Common Stock [Member]
Entity Listings [Line Items]
Entity Common Stock, Shares Outstanding		1,852,608

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 52,283	$ 58,261
Restricted cash	58,726	59,598
Accounts receivable, less allowance for doubtful accounts of $0 as of March 31, 2020 and $0 as of December 31, 2019 (note 3)	37,260	31,091
Other receivables	3,236	2,603
Inventories (note 4)	44,987	44,796
Prepaid expenses	1,985	2,047
Total current assets	198,477	198,396
Property, plant and equipment, net (note 5)	3,495	3,619
Operating lease right-of-use assets, net (note 8)	3,547	3,887
Intangible assets, net	307	344
Deferred tax assets (note 15)	5,212	5,331
Long-term investments (note 10)	6,015	5,934
Other long-term assets	155	192
Total assets	217,208	217,703
Current liabilities:
Short-term borrowings (note 6)	3,892	13,753
Accounts payable	18,616	13,262
Advances from customers	9,236	9,129
Income taxes payable	3,347	3,129
Other payables and accrued expenses (note 7)	14,331	12,874
Current portion of operating lease liability (note 8)	1,345	1,355
Total current liabilities	50,767	53,502
Long-term operating lease liability (note 8)	2,202	2,532
Other long-term liabilities (note 9)	5,830	4,186
Total liabilities	58,799	60,220
Commitments and contingencies (note 17)
Redeemable non-controlling interests (note 13)	59,467	60,162
Stockholders' equity:
Additional paid in capital	84,351	83,487
Accumulated surplus	17,212	15,507
Accumulated other comprehensive loss	(2,623)	(1,675)
Total stockholders' equity	98,942	97,321
Total liabilities, redeemable non-controlling interests, and stockholders' equity	217,208	217,703
Class A Common Stock [Member]
Stockholders' equity:
Common stock	2	2
Class B Common Stock [Member]
Stockholders' equity:
Common stock	$ 0	$ 0

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
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)	16,317,346	16,182,151
Common stock, shares outstanding (in shares)	16,317,346	16,182,151
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)	1,862,608	1,862,608
Common stock, shares outstanding (in shares)	1,862,608	1,862,608

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) [Abstract]
Revenue	$ 24,348	$ 20,479
Cost of revenue	14,120	11,653
Gross profit	10,228	8,826
Operating expenses:
Sales and marketing	3,005	1,869
Research and development	3,677	2,765
General and administrative	2,328	1,941
Total operating expenses, net	9,010	6,575
Income from operations	1,218	2,251
Interest income	335	9
Interest expense	(111)	(139)
Other income (expense), net	677	(261)
Equity income in net income of affiliates	148	116
Income before income taxes	2,267	1,976
Income tax expense (note 15)	(304)	(119)
Net income	1,963	1,857
Less: Net income attributable to redeemable non-controlling interests	258	0
Net income available to common stockholders, basic and diluted	1,705	1,857
Comprehensive income:
Net income	1,963	1,857
Foreign currency translation adjustment	(1,900)	657
Comprehensive Income	63	2,514
Less: Comprehensive income attributable to redeemable non-controlling interests	(694)	0
Comprehensive income attributable to ACM Research, Inc.	$ 757	$ 2,514
Net income attributable to ACM Research, Inc. per common share (note 2):
Basic (in dollars per share)	$ 0.09	$ 0.12
Diluted (in dollars per share)	$ 0.08	$ 0.10
Weighted average common shares outstanding used in computing per share amounts (note 2):
Basic (in shares)	18,120,363	16,044,655
Diluted (in shares)	21,066,636	18,225,317

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - 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 Deficit [Member]	Accumulated Other Comprehensive Loss [Member]	Total
Beginning balance at Dec. 31, 2018	$ 1	$ 0	$ 56,567	$ (3,387)	$ (857)	$ 52,324
Beginning balance (in shares) at Dec. 31, 2018	14,110,315	1,898,423
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to ACM Research, Inc.	$ 0	$ 0	0	1,857	0	1,857
Foreign currency translation adjustment	0	0	0	0	657	657
Exercise of stock options	$ 0	$ 0	60	0	0	60
Exercise of stock options (in shares)	66,375	0
Stock-based compensation	$ 0	$ 0	744	0	0	744
Ending balance at Mar. 31, 2019	$ 1	$ 0	57,371	(1,530)	(200)	55,642
Ending balance (in shares) at Mar. 31, 2019	14,176,690	1,898,423
Beginning balance at Dec. 31, 2019	$ 2	$ 0	83,487	15,507	(1,675)	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 attributable to ACM Research, Inc.	$ 0	$ 0	0	1,705	0	1,705
Foreign currency translation adjustment	0	0	0	0	(948)	(948)
Exercise of stock options	$ 0	$ 0	175	0	0	175
Exercise of stock options (in shares)	70,478	0
Stock-based compensation	$ 0	$ 0	689	0	0	689
Exercise of stock warrant	$ 0	$ 0		0	0	0
Exercise of stock warrant (in shares)	64,717	0
Ending balance at Mar. 31, 2020	$ 2	$ 0	$ 84,351	$ 17,212	$ (2,623)	$ 98,942
Ending balance (in shares) at Mar. 31, 2020	16,317,346	1,862,608

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net income	$ 1,963	$ 1,857
Adjustments to reconcile net income from operations to net cash used in operating activities:
Depreciation and amortization	212	191
Equity income in net income of affiliates	(148)	(116)
Deferred income taxes	35	0
Stock-based compensation	689	744
Net changes in operating assets and liabilities:
Accounts receivable	(6,902)	99
Other receivables	(683)	669
Inventory	(931)	(2,759)
Prepaid expenses	(11)	190
Other long-term assets	36	0
Accounts payable	5,617	(3,757)
Advances from customers	195	45
Income tax payable	263	15
Other payables and accrued expenses	1,779	1,013
Other long-term liabilities	1,715	(1,373)
Net cash provided by (used in) operating activities	3,829	(3,182)
Cash flows from investing activities:
Purchase of property and equipment	(118)	(115)
Purchase of intangible assets	0	(1)
Net cash used in investing activities	(118)	(116)
Cash flows from financing activities:
Proceeds from short-term borrowings	2,681	8,285
Repayments of short-term borrowings	(12,415)	(5,084)
Proceeds from stock option exercise to common stock	175	60
Net cash provided by (used in) financing activities	(9,559)	3,261
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(1,002)	280
Net increase (decrease) in cash, cash equivalents and restricted cash	(6,850)	243
Cash, cash equivalents and restricted cash at beginning of period	117,859	27,124
Cash, cash equivalents and restricted cash at end of period	111,009	27,367
Supplemental disclosure of cash flow information:
Interest paid	111	139
Reconciliation of cash, cash equivalents and restricted cash in condensed consolidated statements of cash flows:
Cash and cash equivalents	52,283	27,367
Restricted cash	58,726	0
Non-cash financing activities:
Warrant conversion to common stock	$ 399	$ 0

DESCRIPTION OF BUSINESS

DESCRIPTION OF BUSINESS	3 Months Ended
	Mar. 31, 2020
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 single-wafer wet cleaning equipment used to improve the manufacturing process and yield for advanced integrated chips. The Company markets and sells its single-wafer wet-cleaning equipment, under the brand name “Ultra C,” based on the Company’s proprietary Space Alternated Phase Shift (“SAPS”) and Timely Energized Bubble Oscillation (“TEBO”) 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. 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 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 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., to manage activities related to addition of future long-term production capacity. The subsidiary was formed with registered capital of RMB 5,000 ($727). As of March 31, 2020, $142 capital had been injected into this subsidiary. In June 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 next three years a listing (the “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. As an initial step in qualifying for the Listing and STAR IPO, in June 2019 ACM Shanghai entered into agreements with seven investors (the “First Tranche Investors”), pursuant to which the First Tranche Investors agreed to pay a purchase price totaling RMB 187,900 (equivalent to $27,300) to ACM Shanghai for shares representing 4.2% of the then-outstanding ACM Shanghai shares. In November 2019 ACM Shanghai entered into agreements with eight PRC-based investment firms (the “Second Tranche Investors”), pursuant to which the Second Tranche Investors agreed to acquire shares of ACM Shanghai for an aggregate of RMB 228,200 (equivalent to $32,400) for the same purchase price per share paid by the First Tranche Investors. Following the issuance of shares to the Second Tranche Investors, 91.7% of the outstanding shares of ACM Shanghai were owned by ACM, 3.8% were owned by the First Tranche Investors, and 4.5% were owned by the Second Tranche Investors. Because the First Tranche Investors and the Second Tranche Investors have the right to require ACM Shanghai to repurchase their ownership interests in ACM Shanghai at a fixed purchase price, those ownership interests are classified as redeemable non-controlling interests. 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 March 31, December 31, ACM Research (Shanghai), Inc. China, May 2006 91.7 % 91.7 % ACM Research (Wuxi), Inc. China, 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 % Shangwei Research (Shanghai), Inc. China, March 2019 91.7 % 91.7 % ACM Research (CA), Inc. USA, June 2019 91.7 % 91.7 % ACM Research (Cayman), Inc. Cayman Islands, April 2019 100.0 % 100.0 %

SIGNIFICANT ACCOUNTING POLICIES

SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2020
SIGNIFICANT ACCOUNTING POLICIES [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	NOTE 2 – SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation and Principles of Consolidation The Company’s 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 and indirectly, controls more than one half 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 herein. The unaudited condensed consolidated financial statements herein should be read in conjunction with the historical consolidated financial statements of the Company for the year ended December 31, 2019 included in ACM’s Annual Report on Form 10-K for the year ended December 31, 2019. The accompanying condensed consolidated balance sheet as of March 31, 2020, the condensed consolidated statements of operations and comprehensive income for the three months ended March 31, 2020 and 2019, the condensed consolidated statements of changes in stockholders’ equity for the three months ended March 31, 2020 and 2019, and the condensed consolidated statements of cash flows for the three months ended March 31, 2020 and 2019 are unaudited. In the opinion of management, the unaudited condensed consolidated financial statements of the Company reflect all adjustments that are necessary for a fair presentation of the Company’s financial position and results of operations. Such adjustments are of a normal recurring nature, unless otherwise noted. The balance sheet as of March 31, 2020 and the results of operations for the three months ended March 31, 2020 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. COVID‑19 originated in Wuhan, China, in December 2019, and a series of emergency quarantine measures taken by the PRC government disrupted domestic business activities in the PRC 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. The situation continues to develop rapidly, however, 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 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. Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the balance sheet date and the reported revenue and expenses during the reported period in the condensed consolidated financial statements and accompanying notes. The Company’s significant accounting estimates and assumptions include, but are not limited to, those used for the valuation and recognition of 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 of the Company believes that the estimates, judgments and assumptions are reasonable, based on information available at the time they are made. Actual results could differ materially from those estimates. Basic and Diluted Net Income per Common Share Basic and diluted net income per common share is calculated as follows: Three Months Ended March 31, 2020 2019 Numerator: Net income $ 1,963 $ 1,857 Net income attributable to redeemable non-controlling interest 258 - Net income available to common stockholders, basic and diluted $ 1,705 $ 1,857 Weighted average shares outstanding, basic 18,120,363 16,044,655 Effect of dilutive securities 2,946,273 2,180,662 Weighted average shares outstanding, diluted 21,066,636 18,225,317 Net income per common share: Basic $ 0.09 $ 0.12 Diluted $ 0.08 $ 0.10 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 months ended March 31, 2020 and 2019, 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 that could share in ACM’s earnings. ACM’s potential dilutive securities consist of warrants and stock options for the three months ended March 31, 2020 and 2019. Concentration of Credit Risk The Company is potentially subject to concentrations of credit risks in its accounts receivable. For the three months ended March 31, 2020 and 2019, the Company’s three largest customers for the period accounted for 97.4% and 62.7% of revenue. As of March 31, 2020 and December 31, 2019 the Company’s three largest customers accounted for 76.1% and 67.7% 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 August 2018, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) 2018-13, Fair Value Measurement (Topic 820) 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 Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815) and Leases (Topic 842), In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes

ACCOUNTS RECEIVABLE

ACCOUNTS RECEIVABLE	3 Months Ended
	Mar. 31, 2020
ACCOUNTS RECEIVABLE [Abstract]
ACCOUNTS RECEIVABLE	NOTE 3 – ACCOUNTS RECEIVABLE At March 31, 2020 and December 31, 2019, accounts receivable consisted of the following: March 31, December 31, Accounts receivable $ 37,260 $ 31,091 Less: Allowance for doubtful accounts - - Total $ 37,260 $ 31,091 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 March 31, 2020 or December 31, 2019. At March 31, 2020 and December 31, 2019, accounts receivable of $0 and $1,433, respectively, were pledged as collateral for borrowings from financial institutions.

INVENTORIES

INVENTORIES	3 Months Ended
	Mar. 31, 2020
INVENTORIES [Abstract]
INVENTORIES	NOTE 4 – INVENTORIES At March 31, 2020 and December 31, 2019, inventory consisted of the following: March 31, December 31, Raw materials $ 15,796 $ 15,105 Work in process 17,622 10,407 Finished goods 11,569 19,284 Total inventory $ 44,987 $ 44,796 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,

PROPERTY, PLANT AND EQUIPMENT, NET	3 Months Ended
	Mar. 31, 2020
PROPERTY, PLANT AND EQUIPMENT, NET [Abstract]
PROPERTY, PLANT AND EQUIPMENT, NET	NOTE 5 – PROPERTY, PLANT AND EQUIPMENT, NET At March 31, 2020 and December 31, 2019, property, plant and equipment consisted of the following: March 31, December 31, Manufacturing equipment $ 3,883 $ 3,902 Office equipment 685 627 Transportation equipment 170 124 Leasehold improvement 1,425 1,442 Total cost 6,163 6,095 Less: Total accumulated depreciation (3,266 ) (3,077 ) Construction in progress 598 601 Total property, plant and equipment, net $ 3,495 $ 3,619 Depreciation expense was $185 and $175 for the three months ended March 31, 2020 and 2019, respectively.

SHORT-TERM BORROWINGS

SHORT-TERM BORROWINGS	3 Months Ended
	Mar. 31, 2020
SHORT-TERM BORROWINGS [Abstract]
SHORT-TERM BORROWINGS	NOTE 6 – SHORT-TERM BORROWINGS At March 31, 2020 and December 31, 2019, short-term borrowings consisted of the following: March 31, December 31, Line of credit up to RMB 50,000 from Bank of Shanghai Pudong Branch, due on January 23, 2020 with an annual interest rate of 5.22%, guaranteed by the Company’s CEO and Cleanchip Technologies Limited.It was fully repaid on January 23, 2020. - 5,057 Line of credit up to RMB 20,000 from Shanghai Rural Commercial Bank, due on February 21, 2020 with an annual interest rate of 5.66%, guaranteed by the Company’s CEO and pledged by accounts receivable.It was fully repaid on February 21, 2020. - 1,433 Line of credit up to RMB 20,000 from Bank of Communications, due on January 18, 2020 with an annual interest rate of 5.66% and fully repaid on January 19, 2020. - 1,433 Line of credit up to RMB 20,000 from Bank of Communications, due on January 22, 2020 with an annual interest rate of 5.66% and fully repaid on January 22, 2020. - 717 Line of credit up to RMB 20,000 from Bank of Communications, due on February 14, 2020 with an annual interest rate of 5.66% and fully repaid on February 14, 2020. - 717 Line of credit up to RMB 50,000 from China Everbright Bank, due on March 25, 2020 with an annual interest rate of 4.94%, guaranteed by the Company’s CEO and fully repaid on March 24, 2020. - 3,250 Line of credit up to RMB 50,000 from China Everbright Bank, due on April 17, 2020 with an annual interest rate of 5.66%, guaranteed by the Company’s CEO. 1,129 1,146 Line of credit up to RMB 50,000 from China Everbright Bank, due on August 24, 2020 with an annual interest rate of 5.22%, guaranteed by the Company’s CEO. 2,681 Line of credit up to KRW 500,000 from Industrial Bank of Korea (IBK), due on July 11, 2020 with an annual interest rate of 4.17%, guaranteed by the ACM-KOREA CEO. 82 Total $ 3,892 $ 13,753 Interest expense related to short-term borrowings amounted to $111 and $139 for the three months ended March 31, 2020 and 2019 respectively.

OTHER PAYABLE AND ACCRUED EXPEN

OTHER PAYABLE AND ACCRUED EXPENSES	3 Months Ended
	Mar. 31, 2020
OTHER PAYABLE AND ACCRUED EXPENSES [Abstract]
OTHER PAYABLE AND ACCRUED EXPENSES	NOTE 7 – OTHER PAYABLE AND ACCRUED EXPENSES At March 31, 2020 and December 31, 2019, other payable and accrued expenses consisted of the following: March 31, December 31, Accrued commissions $ 4,593 $ 4,082 Accrued warranty 3,092 2,811 Accrued payroll 2,775 2,092 Accrued professional fees 403 165 Accrued machine testing fees 1,424 1,456 Others 2,044 2,268 Total $ 14,331 $ 12,874

LEASES

LEASES	3 Months Ended
	Mar. 31, 2020
LEASES [Abstract]
LEASES	NOTE 8 –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 March 31, 2020 2019 Operating lease cost $ 377 $ 437 Short-term lease cost 50 18 Lease cost $ 427 $ 455 Supplemental cash flow information related to operating leases was as follows for the period ended March 31, 2020 and 2019 respectively: Three Months Ended March 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash outflow from operating leases $ 427 $ 455 Maturities of lease liabilities for all operating leases were as follows as of March 31, 2020: December 31, 2020 $ 1,128 2021 1,488 2022 1,495 2023 53 2024 13 Total lease payments 4,177 Less: Interest (630 ) Present value of lease liabilities $ 3,547 The weighted average remaining lease terms and discount rates for all operating leases were as follows as of March 31, 2020: March 31, 2020 December 31, 2019 Remaining lease term and discount rate: Weighted average remaining lease term (years) 2.80 3.02 Weighted average discount rate 5.43 % 5.43 %

OTHER LONG-TERM LIABILITIES

OTHER LONG-TERM LIABILITIES	3 Months Ended
	Mar. 31, 2020
OTHER LONG-TERM LIABILITIES [Abstract]
OTHER LONG-TERM LIABILITIES	NOTE 9 – OTHER LONG-TERM LIABILITIES Other long-term liabilities represent subsidies received from several governmental authorities, including China’s Ministry of Science and Technology, the Shanghai Municipal Commission of Economy and Information, and the Shanghai Science and Technology Committee, for development and commercialization of certain technology but not yet recognized. As of March 31, 2020, and December 31, 2019, other long-term liabilities consisted of the following unearned government subsidies: h March 31, December 31, Subsidies to Stress Free Polishing project, commenced in 2008 and 2017 $ 1,191 $ 1,251 Subsidies to Electro Copper Plating project, commenced in 2014 2,445 2,666 Subsidies to Polytetrafluoroethylene, commenced in 2018 123 135 Subsidies to Tahoe-Single Bench Clean,commenced in 2020 1,910 - Other 161 134 Total $ 5,830 $ 4,186

LONG-TERM INVESTMENT

LONG-TERM INVESTMENT	3 Months Ended
	Mar. 31, 2020
LONG-TERM INVESTMENT [Abstract]
LONG-TERM INVESTMENT	NOTE 10 – LONG-TERM INVESTMENT On September 6, 2017, ACM and Ninebell Co., Ltd. (“Ninebell”), a Korean company that is one of the Company’s principal materials 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 components 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) (“Hefei Shixi”), a Chinese limited partnership based in Hefei, China. Pursuant to such Partnership Agreement, on September 30, 2019, ACM Shanghai invested $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. March 31, December 31, Ninebell $ 1,694 $ 1,538 Shengyi 109 107 Hefei Shixi 4,212 4,289 Total $ 6,015 $ 5,934

RELATED PARTY BALANCES AND TRAN

RELATED PARTY BALANCES AND TRANSACTIONS	3 Months Ended
	Mar. 31, 2020
RELATED PARTY BALANCES AND TRANSACTIONS [Abstract]
RELATED PARTY BALANCES AND TRANSACTIONS	NOTE 11– RELATED PARTY BALANCES AND TRANSACTIONS Three months ended March 31 Purchase of materials 2020 2019 Ninebell $ 2,153 $ 2,320 Shengyi 58 - Total $ 2,211 $ 2,320 Prepaid expenses March 31, 2020 December 31, 2019 Ninebell $ 648 $ 348 Accounts payable March 31, 2020 December 31, 2019 Ninebell $ 2,604 $ 727 Shengyi 189 488 Total $ 2,793 $ 1,215 On December 9, 2016, Shengxin (Shanghai) Management Consulting Limited Partnership (“SMC”), a PRC limited partnership owned by employees of ACM Shanghai, including Jian Wang, the Chief Executive Officer and President of ACM Shanghai and the brother of David H. Wang (a related party), delivered RMB 20,124 ($2,981 as of the close of business on such date) in cash (the “SMC Investment”) to ACM Shanghai for potential investment pursuant to terms to be subsequently negotiated. On March 14, 2017, ACM, ACM Shanghai and SMC entered into a securities purchase agreement (the “SMC Agreement”) pursuant to which, in exchange for the SMC Investment, (a) ACM issued to SMC a warrant (the “SMC Warrant”) exercisable, for cash or on a cashless basis, to purchase, at any time on or before May 17, 2023, all, but not less than all, of 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 exercise of the SMC Warrant. On March 30, 2018, SMC exercised the SMC Warrant in full and purchased 397,502 shares of Class A common stock (note 12). SMC borrowed the funds to pay the SMC Warrant exercise price pursuant to a senior secured promissory note in the principal amount of $2,981 issued to the Company (the “SMC Note”). The note bears interest at a rate of 3.01% per annum and matures on August 17, 2023 and is secured by a pledge of the shares issued upon exercise of the SMC Warrant. As described in the following paragraph, in the third quarter of 2019 ACM repurchased a total of 154,821 of the SMC 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 the remaining $882 was paid to SMC. In a separate transaction in August, 2019, ACM Shanghai repaid $1,161 of the SMC Investment in cash. On August 14, 2019, ACM entered into an equity purchase agreement under which it agreed to repurchase, at a price per share of $13.195 (the net proceeds per share ACM received in a public offering of Class A common stock, as described in note 12), shares of Class A common stock from certain directors, employees and SMC upon the exercise of the underwriters’ over-allotment option in connection with the public offering in August 2019. The total consideration to the directors, employees and SMC, in exchange for their surrender of an aggregate of 214,286 shares of Class A common stock and cancellation of options to acquire 53,571 shares of Class A common stock amounted to a total of $3,403, which was based at a price of $13.195 per share equal to the net proceeds per share ACM received from the over-allotment option in connection with the offering.

COMMON STOCK

COMMON STOCK	3 Months Ended
	Mar. 31, 2020
COMMON STOCK [Abstract]
COMMON STOCK	NOTE 12 – 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 March 31, 2020 and 2019, ACM issued 70,478 and 66,375 shares of Class A common stock upon option exercises by employees and non-employees, respectively. During the three months ended March 31, 2020, ACM issued 64,717 shares of Class A common stock upon a cashless warrant exercise by a non-employee. There were issued and outstanding 16,317,346 shares of Class A common stock and 1,862,608 shares of Class B common stock at March 31, 2020, and 16,182,151 shares of Class A common stock and 1,862,608 shares of Class B common stock at December 31, 2019.

REDEEMABLE NON-CONTROLLING INTE

REDEEMABLE NON-CONTROLLING INTERESTS	3 Months Ended
	Mar. 31, 2020
REDEEMABLE NON-CONTROLLING INTERESTS [Abstract]
REDEEMABLE NON-CONTROLLING INTERESTS	NOTE 13 – REDEEMABLE NON-CONTROLLING INTERESTS The components of the change in the redeemable non-controlling interests for the three months ended March 31, 2020 are presented in the following table: Balance at December 31, 2019 $ 60,162 Net income attributable to redeemable non-controlling interests 258 Effect of foreign currency translation loss attributable to redeemable non-controlling interests (953 ) Balance at March 31, 2020 $ 59,467

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2020
STOCK-BASED COMPENSATION [Abstract]
STOCK-BASED COMPENSATION	NOTE 14– STOCK-BASED COMPENSATION ACM’s stock-based compensation consists of employee and non-employee awards issued under the 1998 Stock Option Plan, the 2016 Omnibus Incentive Plan and as standalone options. In January 2020, ACM Shanghai, adopted a 2019 Stock Option Incentive Plan (the “Subsidiary Stock Option Plan”) which provides for, among other incentives, the granting to officers, directors, employees of ACM Shanghai options to purchase shares in ACM Shanghai’s common stock. The fair value of the stock options granted is estimated at the date of grant using the Black-Scholes option pricing model using assumptions generally consistent with those used for Company stock options. Because ACM Shanghai is 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. The following table summarizes the components of stock-based compensation expense included in the consolidated statements of operations: Three Months Ended March 31, 2020 2019 Stock-Based Compensation Expense: Cost of revenue $ 45 $ 30 Sales and marketing expense 94 34 Research and development expense 187 86 General and administrative expense 363 594 $ 689 $ 744 Three Months Ended March 31, 2020 2019 Stock-based compensation expense by type: Employee stock purchase plan $ 431 $ 221 Non-employee stock purchase plan 172 523 Subsidiary option grants 86 - $ 689 $ 744 Employee Awards The following table summarizes the Company’s employee share option activities during the three months ended March 31, 2020: Number of Weighted Weighted Average Exercise Price Weighed Average Outstanding at December 31, 2019 2,994,063 $ 2.59 $ 6.77 7.05 years Granted 20,000 9.11 22.95 Exercised (26,032 ) 1.31 3.60 Expired - - - Forfeited/cancelled (22,000 ) 6.46 16.74 Outstanding at March 31, 2020 2,966,031 $ 2.61 $ 6.83 6.81 years Vested and exercisable at March 31, 2020 1,859,052 During the three months ended March 31, 2020 and 2019, the Company recognized employee stock-based compensation expense $431 and $221, respectively. As of March 31, 2020 and December 31, 2019, $4,317 and $4,712, respectively, of total unrecognized 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 1.29 years and 1.47 years, respectively. Total recognized compensation cost may be adjusted for future changes in estimated forfeitures. Non-employee Awards The following table summarizes the Company’s non-employee stock option activities during the three months ended March 31, 2020: Number of Weighted Weighted Average Exercise Price Weighted Average Remaining Contractual Term Outstanding at December 31, 2019 1,101,613 $ 0.82 $ 2.69 5.85 years Granted 20,000 10.29 25.60 Exercised (44,446 ) 0.44 1.82 Expired - Forfeited/cancelled - Outstanding at March 31, 2020 1,077,167 $ 1.01 $ 3.15 5.75 years Vested and exercisable at March 31, 2020 1,007,076 During the three months ended March 31, 2020 and 2019, 523 As of March 31, 2020 and December 31, 2019, $419 and $406, 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 0.22 years and 0.23 years, respectively. Total recognized compensation cost may be adjusted for future changes in estimated forfeitures. Subsidiary Option Grants The following table summarizes the ACM Shanghai employee stock option activities during the three months ended March 31, 2020: Number of Weighted Weighted Average Exercise Price Weighed Average Outstanding at December 31, 2019 - $ - $ - - Granted 5,869,808 0.22 1.87 Exercised - - - Expired - - - Forfeited/cancelled (192,308 ) 0.23 1.87 Outstanding at March 31, 2020 5,677,500 $ 0.22 $ 1.87 4.26 years Vested and exercisable at March 31, 2020 - During the three months ended March 31, 2020, As of March 31, 2020 $1,106 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 3.26 years. Total recognized compensation cost may be adjusted for future changes in estimated forfeitures.

INCOME TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2020
INCOME TAXES [Abstract]
INCOME TAXES	NOTE 15 – 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 maintained a partial consolidated valuation allowance for the three months ended March 31, 2020. The Company accounts for uncertain tax positions in accordance with the authoritative guidance on income taxes under which the Company may only recognize or continue to recognize tax positions that meet a more likely than not threshold. The Company recognizes accrued interest and penalties related to unrecognized tax benefits as a component of the provision for income taxes. The Company’s effective tax rate differs from statutory rates of 21% for U.S. federal income tax purposes and 15% to 25% for Chinese income tax purposes due to the effects of the valuation allowance and certain permanent differences from book-tax differences. As a result, the Company recorded income tax expense of $304 and $119 during the three months ended March 31, 2020 and 2019, respectively. As of March 31, 2020, the Company’s total unrecognized tax benefits were $44, which would not 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 three months ended March 31, 2020. 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, 2009 through December 31, 2019. 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. Income Tax Expense The following presents components of income tax expense for the indicated periods: Three Months Ended March 31, 2020 2019 (in thousands) Current: U.S. federal $ (10 ) $ - U.S. state - - Foreign (257 ) - Total current tax expense (267 ) - Deferred: U.S. federal (28 ) - U.S. state - - Foreign (9 ) (119 ) Total deferred tax benefit (37 ) (119 ) Total income tax expense $ (304 ) $ (119 ) Our effective tax rate differs from statutory rates of 21% for U.S. federal income tax purposes and 15% to 25% for Chinese income tax purposes due to the effects of the valuation allowance and certain permanent differences as it pertains to book-tax differences in the value of client equity securities received for services. Our two PRC subsidiaries, ACM Shanghai and ACM Wuxi, are liable for PRC corporate income taxes at the rates of 15% 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. We file 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 2016. To the extent we have tax attribute carryforwards, the tax years in which the attribute was generated may still be adjusted upon examination by the Internal Revenue Service or state or foreign tax authorities to the extent utilized in a future period. The Coronavirus Aid, Relief, and Economic Security Act (CARES Act) was enacted on March 27, 2020. It contains several provisions that may have financial statement effects. Key aspects of the CARES Act include the following: • Repealed the 80% taxable income limitation for 2018, 2019 and 2020. Also allows those years to be carried back up to five years • Allows corporations to claim 100% of AMT credits in 2019. It also provides for an election to take the entire refundable credit amount in 2018 • Section 163(j) ATI limit raised from 30% to 50% for businesses • Technical corrections to TCJA for Qualified Improvement Property (“QIP”). Designates as 15-year property for depreciation purposes, which makes QIP a category eligible for 100% bonus depreciation The CARES Act is not expected have a material impact on income taxes in the Company’s financial statements.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2020
COMMITMENTS AND CONTINGENCIES [Abstract]
COMMITMENTS AND CONTINGENCIES	NOTE 16 – 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 March 31, 2020, the Company had $636 of open capital commitments. From time to time the Company is subject to legal proceedings, including claims in the ordinary course of business and claims with respect to patent infringements. As of March 31, 2020, the Company did not have any legal proceedings.

SIGNIFICANT ACCOUNTING POLICI_2

SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2020
SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The Company’s 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 and indirectly, controls more than one half 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 herein. The unaudited condensed consolidated financial statements herein should be read in conjunction with the historical consolidated financial statements of the Company for the year ended December 31, 2019 included in ACM’s Annual Report on Form 10-K for the year ended December 31, 2019. The accompanying condensed consolidated balance sheet as of March 31, 2020, the condensed consolidated statements of operations and comprehensive income for the three months ended March 31, 2020 and 2019, the condensed consolidated statements of changes in stockholders’ equity for the three months ended March 31, 2020 and 2019, and the condensed consolidated statements of cash flows for the three months ended March 31, 2020 and 2019 are unaudited. In the opinion of management, the unaudited condensed consolidated financial statements of the Company reflect all adjustments that are necessary for a fair presentation of the Company’s financial position and results of operations. Such adjustments are of a normal recurring nature, unless otherwise noted. The balance sheet as of March 31, 2020 and the results of operations for the three months ended March 31, 2020 are not necessarily indicative of the results to be expected for any future period.
COVID-19 Assessment	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. COVID‑19 originated in Wuhan, China, in December 2019, and a series of emergency quarantine measures taken by the PRC government disrupted domestic business activities in the PRC 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. The situation continues to develop rapidly, however, 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 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.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the balance sheet date and the reported revenue and expenses during the reported period in the condensed consolidated financial statements and accompanying notes. The Company’s significant accounting estimates and assumptions include, but are not limited to, those used for the valuation and recognition of 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 of the Company believes that the estimates, judgments and assumptions are reasonable, based on information available at the time they are made. Actual results could differ materially from those estimates.
Basic and Diluted Net Income per Common Share	Basic and Diluted Net Income per Common Share Basic and diluted net income per common share is calculated as follows: Three Months Ended March 31, 2020 2019 Numerator: Net income $ 1,963 $ 1,857 Net income attributable to redeemable non-controlling interest 258 - Net income available to common stockholders, basic and diluted $ 1,705 $ 1,857 Weighted average shares outstanding, basic 18,120,363 16,044,655 Effect of dilutive securities 2,946,273 2,180,662 Weighted average shares outstanding, diluted 21,066,636 18,225,317 Net income per common share: Basic $ 0.09 $ 0.12 Diluted $ 0.08 $ 0.10 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 months ended March 31, 2020 and 2019, 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 that could share in ACM’s earnings. ACM’s potential dilutive securities consist of warrants and stock options for the three months ended March 31, 2020 and 2019.
Concentration of Credit Risk	Concentration of Credit Risk The Company is potentially subject to concentrations of credit risks in its accounts receivable. For the three months ended March 31, 2020 and 2019, the Company’s three largest customers for the period accounted for 97.4% and 62.7% of revenue. As of March 31, 2020 and December 31, 2019 the Company’s three largest customers accounted for 76.1% and 67.7% 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	Recent Accounting Pronouncements Recently Adopted Accounting Pronouncements In August 2018, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) 2018-13, Fair Value Measurement (Topic 820) 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 Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815) and Leases (Topic 842), In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes

DESCRIPTION OF BUSINESS (Tables

DESCRIPTION OF BUSINESS (Tables)	3 Months Ended
	Mar. 31, 2020
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 March 31, December 31, ACM Research (Shanghai), Inc. China, May 2006 91.7 % 91.7 % ACM Research (Wuxi), Inc. China, 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 % Shangwei Research (Shanghai), Inc. China, March 2019 91.7 % 91.7 % ACM Research (CA), Inc. USA, June 2019 91.7 % 91.7 % ACM Research (Cayman), Inc. Cayman Islands, April 2019 100.0 % 100.0 %

SIGNIFICANT ACCOUNTING POLICI_3

SIGNIFICANT ACCOUNTING POLICIES (Tables)	3 Months Ended
	Mar. 31, 2020
SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Basic and Diluted Net Income per Common Share	Basic and diluted net income per common share is calculated as follows: Three Months Ended March 31, 2020 2019 Numerator: Net income $ 1,963 $ 1,857 Net income attributable to redeemable non-controlling interest 258 - Net income available to common stockholders, basic and diluted $ 1,705 $ 1,857 Weighted average shares outstanding, basic 18,120,363 16,044,655 Effect of dilutive securities 2,946,273 2,180,662 Weighted average shares outstanding, diluted 21,066,636 18,225,317 Net income per common share: Basic $ 0.09 $ 0.12 Diluted $ 0.08 $ 0.10

ACCOUNTS RECEIVABLE (Tables)

ACCOUNTS RECEIVABLE (Tables)	3 Months Ended
	Mar. 31, 2020
ACCOUNTS RECEIVABLE [Abstract]
Accounts Receivable	At March 31, 2020 and December 31, 2019, accounts receivable consisted of the following: March 31, December 31, Accounts receivable $ 37,260 $ 31,091 Less: Allowance for doubtful accounts - - Total $ 37,260 $ 31,091

INVENTORIES (Tables)

INVENTORIES (Tables)	3 Months Ended
	Mar. 31, 2020
INVENTORIES [Abstract]
Inventory	At March 31, 2020 and December 31, 2019, inventory consisted of the following: March 31, December 31, Raw materials $ 15,796 $ 15,105 Work in process 17,622 10,407 Finished goods 11,569 19,284 Total inventory $ 44,987 $ 44,796

PROPERTY, PLANT AND EQUIPMENT_2

PROPERTY, PLANT AND EQUIPMENT, NET (Tables)	3 Months Ended
	Mar. 31, 2020
PROPERTY, PLANT AND EQUIPMENT, NET [Abstract]
Property, Plant and Equipment	At March 31, 2020 and December 31, 2019, property, plant and equipment consisted of the following: March 31, December 31, Manufacturing equipment $ 3,883 $ 3,902 Office equipment 685 627 Transportation equipment 170 124 Leasehold improvement 1,425 1,442 Total cost 6,163 6,095 Less: Total accumulated depreciation (3,266 ) (3,077 ) Construction in progress 598 601 Total property, plant and equipment, net $ 3,495 $ 3,619

SHORT-TERM BORROWINGS (Tables)

SHORT-TERM BORROWINGS (Tables)	3 Months Ended
	Mar. 31, 2020
SHORT-TERM BORROWINGS [Abstract]
Short-Term Borrowings	At March 31, 2020 and December 31, 2019, short-term borrowings consisted of the following: March 31, December 31, Line of credit up to RMB 50,000 from Bank of Shanghai Pudong Branch, due on January 23, 2020 with an annual interest rate of 5.22%, guaranteed by the Company’s CEO and Cleanchip Technologies Limited.It was fully repaid on January 23, 2020. - 5,057 Line of credit up to RMB 20,000 from Shanghai Rural Commercial Bank, due on February 21, 2020 with an annual interest rate of 5.66%, guaranteed by the Company’s CEO and pledged by accounts receivable.It was fully repaid on February 21, 2020. - 1,433 Line of credit up to RMB 20,000 from Bank of Communications, due on January 18, 2020 with an annual interest rate of 5.66% and fully repaid on January 19, 2020. - 1,433 Line of credit up to RMB 20,000 from Bank of Communications, due on January 22, 2020 with an annual interest rate of 5.66% and fully repaid on January 22, 2020. - 717 Line of credit up to RMB 20,000 from Bank of Communications, due on February 14, 2020 with an annual interest rate of 5.66% and fully repaid on February 14, 2020. - 717 Line of credit up to RMB 50,000 from China Everbright Bank, due on March 25, 2020 with an annual interest rate of 4.94%, guaranteed by the Company’s CEO and fully repaid on March 24, 2020. - 3,250 Line of credit up to RMB 50,000 from China Everbright Bank, due on April 17, 2020 with an annual interest rate of 5.66%, guaranteed by the Company’s CEO. 1,129 1,146 Line of credit up to RMB 50,000 from China Everbright Bank, due on August 24, 2020 with an annual interest rate of 5.22%, guaranteed by the Company’s CEO. 2,681 Line of credit up to KRW 500,000 from Industrial Bank of Korea (IBK), due on July 11, 2020 with an annual interest rate of 4.17%, guaranteed by the ACM-KOREA CEO. 82 Total $ 3,892 $ 13,753

OTHER PAYABLE AND ACCRUED EXP_2

OTHER PAYABLE AND ACCRUED EXPENSES (Tables)	3 Months Ended
	Mar. 31, 2020
OTHER PAYABLE AND ACCRUED EXPENSES [Abstract]
Other Payable and Accrued Expenses	At March 31, 2020 and December 31, 2019, other payable and accrued expenses consisted of the following: March 31, December 31, Accrued commissions $ 4,593 $ 4,082 Accrued warranty 3,092 2,811 Accrued payroll 2,775 2,092 Accrued professional fees 403 165 Accrued machine testing fees 1,424 1,456 Others 2,044 2,268 Total $ 14,331 $ 12,874

LEASES (Tables)

LEASES (Tables)	3 Months Ended
	Mar. 31, 2020
LEASES [Abstract]
Components of Lease Expense	The components of lease expense were as follows: Three Months Ended March 31, 2020 2019 Operating lease cost $ 377 $ 437 Short-term lease cost 50 18 Lease cost $ 427 $ 455
Supplemental Cash Flow Information Related to Operating Leases	Supplemental cash flow information related to operating leases was as follows for the period ended March 31, 2020 and 2019 respectively: Three Months Ended March 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash outflow from operating leases $ 427 $ 455
Maturities of Lease Liabilities for Operating Leases	Maturities of lease liabilities for all operating leases were as follows as of March 31, 2020: December 31, 2020 $ 1,128 2021 1,488 2022 1,495 2023 53 2024 13 Total lease payments 4,177 Less: Interest (630 ) Present value of lease liabilities $ 3,547
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 March 31, 2020: March 31, 2020 December 31, 2019 Remaining lease term and discount rate: Weighted average remaining lease term (years) 2.80 3.02 Weighted average discount rate 5.43 % 5.43 %

OTHER LONG-TERM LIABILITIES (Ta

OTHER LONG-TERM LIABILITIES (Tables)	3 Months Ended
	Mar. 31, 2020
OTHER LONG-TERM LIABILITIES [Abstract]
Other Long-Term Liabilities	Other long-term liabilities represent subsidies received from several governmental authorities, including China’s Ministry of Science and Technology, the Shanghai Municipal Commission of Economy and Information, and the Shanghai Science and Technology Committee, for development and commercialization of certain technology but not yet recognized. As of March 31, 2020, and December 31, 2019, other long-term liabilities consisted of the following unearned government subsidies: h March 31, December 31, Subsidies to Stress Free Polishing project, commenced in 2008 and 2017 $ 1,191 $ 1,251 Subsidies to Electro Copper Plating project, commenced in 2014 2,445 2,666 Subsidies to Polytetrafluoroethylene, commenced in 2018 123 135 Subsidies to Tahoe-Single Bench Clean,commenced in 2020 1,910 - Other 161 134 Total $ 5,830 $ 4,186

LONG-TERM INVESTMENT (Tables)

LONG-TERM INVESTMENT (Tables)	3 Months Ended
	Mar. 31, 2020
LONG-TERM INVESTMENT [Abstract]
Long-Term Investment	The investment in Hefei Shixi Chanheng Integrated Circuit Industry Venture Capital Fund Partnership (LP) is accounted for under the equity method. March 31, December 31, Ninebell $ 1,694 $ 1,538 Shengyi 109 107 Hefei Shixi 4,212 4,289 Total $ 6,015 $ 5,934

RELATED PARTY BALANCES AND TR_2

RELATED PARTY BALANCES AND TRANSACTIONS (Tables)	3 Months Ended
	Mar. 31, 2020
RELATED PARTY BALANCES AND TRANSACTIONS [Abstract]
Related Party Balances and Transactions	Three months ended March 31 Purchase of materials 2020 2019 Ninebell $ 2,153 $ 2,320 Shengyi 58 - Total $ 2,211 $ 2,320 Prepaid expenses March 31, 2020 December 31, 2019 Ninebell $ 648 $ 348 Accounts payable March 31, 2020 December 31, 2019 Ninebell $ 2,604 $ 727 Shengyi 189 488 Total $ 2,793 $ 1,215

REDEEMABLE NON-CONTROLLING IN_2

REDEEMABLE NON-CONTROLLING INTERESTS (Tables)	3 Months Ended
	Mar. 31, 2020
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 three months ended March 31, 2020 are presented in the following table: Balance at December 31, 2019 $ 60,162 Net income attributable to redeemable non-controlling interests 258 Effect of foreign currency translation loss attributable to redeemable non-controlling interests (953 ) Balance at March 31, 2020 $ 59,467

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2020
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 March 31, 2020 2019 Stock-Based Compensation Expense: Cost of revenue $ 45 $ 30 Sales and marketing expense 94 34 Research and development expense 187 86 General and administrative expense 363 594 $ 689 $ 744 Three Months Ended March 31, 2020 2019 Stock-based compensation expense by type: Employee stock purchase plan $ 431 $ 221 Non-employee stock purchase plan 172 523 Subsidiary option grants 86 - $ 689 $ 744
Employee Share Option [Member]
Stock-Based Compensation [Abstract]
Summary of Share Option Activities	The following table summarizes the Company’s employee share option activities during the three months ended March 31, 2020: Number of Weighted Weighted Average Exercise Price Weighed Average Outstanding at December 31, 2019 2,994,063 $ 2.59 $ 6.77 7.05 years Granted 20,000 9.11 22.95 Exercised (26,032 ) 1.31 3.60 Expired - - - Forfeited/cancelled (22,000 ) 6.46 16.74 Outstanding at March 31, 2020 2,966,031 $ 2.61 $ 6.83 6.81 years Vested and exercisable at March 31, 2020 1,859,052
Employee Share Option [Member] | ACM Shanghai [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 March 31, 2020: Number of Weighted Weighted Average Exercise Price Weighed Average Outstanding at December 31, 2019 - $ - $ - - Granted 5,869,808 0.22 1.87 Exercised - - - Expired - - - Forfeited/cancelled (192,308 ) 0.23 1.87 Outstanding at March 31, 2020 5,677,500 $ 0.22 $ 1.87 4.26 years Vested and exercisable at March 31, 2020 -
Non-Employee Stock Option [Member]
Stock-Based Compensation [Abstract]
Summary of Share Option Activities	The following table summarizes the Company’s non-employee stock option activities during the three months ended March 31, 2020: Number of Weighted Weighted Average Exercise Price Weighted Average Remaining Contractual Term Outstanding at December 31, 2019 1,101,613 $ 0.82 $ 2.69 5.85 years Granted 20,000 10.29 25.60 Exercised (44,446 ) 0.44 1.82 Expired - Forfeited/cancelled - Outstanding at March 31, 2020 1,077,167 $ 1.01 $ 3.15 5.75 years Vested and exercisable at March 31, 2020 1,007,076

INCOME TAXES (Tables)

INCOME TAXES (Tables)	3 Months Ended
	Mar. 31, 2020
INCOME TAXES [Abstract]
Components of Income Tax Expense	The following presents components of income tax expense for the indicated periods: Three Months Ended March 31, 2020 2019 (in thousands) Current: U.S. federal $ (10 ) $ - U.S. state - - Foreign (257 ) - Total current tax expense (267 ) - Deferred: U.S. federal (28 ) - U.S. state - - Foreign (9 ) (119 ) Total deferred tax benefit (37 ) (119 ) Total income tax expense $ (304 ) $ (119 )

DESCRIPTION OF BUSINESS (Detail

DESCRIPTION OF BUSINESS (Details) ¥ in Thousands, $ in Thousands	Nov. 29, 2019USD ($)Investor	Nov. 29, 2019CNY (¥)Investor	Jun. 30, 2019USD ($)Investor	Jun. 30, 2019CNY (¥)Investor	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Mar. 31, 2019USD ($)	Mar. 31, 2019CNY (¥)
ACM Research (Shanghai), Inc. [Member]
Description of Business [Abstract]
Term to complete listing of shares			3 years	3 years
Name of subsidiaries						ACM Research (Shanghai), Inc.
Date and place of Incorporation					China, May 2006
Effective interest held as at					91.70%	91.70%
ACM Research (Shanghai), Inc. [Member] | First Tranche Investors [Member]
Description of Business [Abstract]
Purchase of equity interest percentage						3.80%
Number of investors with agreements entered | Investor			7	7
Purchase price of stock agreed by investors			$ 27,300	¥ 187,900
Percentage of outstanding shares to be sold to investors			4.20%	4.20%
ACM Research (Shanghai), Inc. [Member] | Second Tranche Investors [Member]
Description of Business [Abstract]
Purchase of equity interest percentage						4.50%
Number of investors with agreements entered | Investor	8	8
Purchase price of stock agreed by investors	$ 32,400	¥ 228,200
ACM Research (Wuxi), Inc. [Member]
Description of Business [Abstract]
Name of subsidiaries						ACM Research (Wuxi), Inc.
Date and place of Incorporation					China, 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%
Shangwei Research (Shanghai), Inc. [Member]
Description of Business [Abstract]
Purchase of equity interest percentage						91.70%
Registered capital							$ 727	¥ 5,000
Capital injected in subsidiary | $					$ 142
Name of subsidiaries						Shangwei Research (Shanghai), Inc.
Date and place of Incorporation					China, 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, June 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%

SIGNIFICANT ACCOUNTING POLICI_4

SIGNIFICANT ACCOUNTING POLICIES, Basic and Diluted Net Income per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Numerator [Abstract]
Net income	$ 1,963	$ 1,857
Net income attributable to redeemable non-controlling interest	258	0
Net income available to common stockholders, basic and diluted	$ 1,705	$ 1,857
Weighted average shares outstanding, basic (in shares)	18,120,363	16,044,655
Effect of dilutive securities (in shares)	2,946,273	2,180,662
Weighted average shares outstanding, diluted (in shares)	21,066,636	18,225,317
Net income per common share [Abstract]
Basic (in dollars per share)	$ 0.09	$ 0.12
Diluted (in dollars per share)	$ 0.08	$ 0.10

SIGNIFICANT ACCOUNTING POLICI_5

SIGNIFICANT ACCOUNTING POLICIES, Concentration of Credit Risk (Details) - Customer	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accounts Receivable [Member]
Concentration of Credit Risk [Abstract]
Number of major customers	3	3
Concentration of credit risk	97.40%	62.70%
Revenue Benchmark [Member]
Concentration of Credit Risk [Abstract]
Number of major customers	3	3
Concentration of credit risk	76.10%	67.70%

ACCOUNTS RECEIVABLE (Details)

ACCOUNTS RECEIVABLE (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accounts Receivable [Abstract]
Accounts receivable	$ 37,260	$ 31,091
Less: allowance for doubtful accounts	0	0
Total	37,260	31,091
Accounts receivable pledged as collateral for borrowings	$ 0	$ 1,433

INVENTORIES (Details)

INVENTORIES (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Inventory [Abstract]
Raw materials	$ 15,796	$ 15,105
Work in process	17,622	10,407
Finished goods	11,569	19,284
Total inventory	$ 44,987	$ 44,796

PROPERTY, PLANT AND EQUIPMENT_3

PROPERTY, PLANT AND EQUIPMENT, NET (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Total cost	$ 6,163		$ 6,095
Less: Total accumulated depreciation	(3,266)		(3,077)
Construction in progress	598		601
Total property, plant and equipment, net	3,495		3,619
Depreciation expense	185	$ 175
Manufacturing Equipment [Member]
Property, Plant and Equipment [Abstract]
Total cost	3,883		3,902
Office Equipment [Member]
Property, Plant and Equipment [Abstract]
Total cost	685		627
Transportation Equipment [Member]
Property, Plant and Equipment [Abstract]
Total cost	170		124
Leasehold Improvement [Member]
Property, Plant and Equipment [Abstract]
Total cost	$ 1,425		$ 1,442

SHORT-TERM BORROWINGS (Details)

SHORT-TERM BORROWINGS (Details) ₩ in Thousands, ¥ in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)	Mar. 31, 2019USD ($)	Mar. 31, 2020CNY (¥)	Mar. 31, 2020KRW (₩)	Dec. 31, 2019USD ($)
Short-Term Borrowings [Abstract]
Short-term borrowings	$ 3,892				$ 13,753
Interest expense related to short-term borrowings	111	$ 139
Line of Credit Due on January 23, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	$ 0				5,057
Maximum borrowing capacity | ¥			¥ 50,000
Annual interest rate	5.22%
Line of credit due date	Jan. 23, 2020
Line of Credit Due on February 21, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	$ 0				1,433
Maximum borrowing capacity | ¥			20,000
Annual interest rate	5.66%
Line of credit due date	Feb. 21, 2020
Line of Credit Due on January 18, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	$ 0				1,433
Maximum borrowing capacity | ¥			20,000
Annual interest rate	5.66%
Line of credit due date	Jan. 19, 2020
Line of Credit Due on January 22, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	$ 0				717
Maximum borrowing capacity | ¥			20,000
Annual interest rate	5.66%
Line of credit due date	Jan. 22, 2020
Line of Credit Due on February 14, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	$ 0				717
Maximum borrowing capacity | ¥			20,000
Annual interest rate	5.66%
Line of credit due date	Feb. 14, 2020
Line of Credit Due on March 25, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	$ 0				3,250
Maximum borrowing capacity | ¥			50,000
Annual interest rate	4.94%
Line of credit due date	Mar. 24, 2020
Line of Credit Due on April 17, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	$ 1,129				1,146
Maximum borrowing capacity | ¥			50,000
Annual interest rate	5.66%
Line of credit due date	Apr. 17, 2020
Line of Credit Due on August 24, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	$ 2,681				0
Maximum borrowing capacity | ¥			¥ 50,000
Annual interest rate	5.22%
Line of credit due date	Aug. 24, 2020
Line of Credit Due on July 11, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	$ 82				$ 0
Maximum borrowing capacity | ₩				₩ 500,000
Annual interest rate	4.17%
Line of credit due date	Jul. 11, 2020

OTHER PAYABLE AND ACCRUED EXP_3

OTHER PAYABLE AND ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
OTHER PAYABLE AND ACCRUED EXPENSES [Abstract]
Accrued commissions	$ 4,593	$ 4,082
Accrued warranty	3,092	2,811
Accrued payroll	2,775	2,092
Accrued professional fees	403	165
Accrued machine testing fees	1,424	1,456
Others	2,044	2,268
Total	$ 14,331	$ 12,874

LEASES (Details)

LEASES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Components of lease expense [Abstract]
Operating lease cost	$ 377	$ 437
Short-term lease cost	50	18
Lease cost	427	455
Cash paid for amounts included in the measurement of lease liabilities [Abstract]
Operating cash outflow from operating leases	427	$ 455
Maturities of lease liabilities [Abstract]
2020	1,128
2021	1,488
2022	1,495
2023	53
2024	13
Total lease payments	4,177
Less: interest	(630)
Present value of lease liabilities	$ 3,547
Weighted average remaining lease terms and discount rates [Abstract]
Weighted average remaining lease term	2 years 9 months 18 days		3 years 7 days
Weighted average discount rate	5.43%		5.43%

OTHER LONG-TERM LIABILITIES (De

OTHER LONG-TERM LIABILITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Other Long-term Liabilities [Abstract]
Other long-term liabilities	$ 5,830	$ 4,186
Subsidies to Stress Free Polishing Project, Commenced in 2008 and 2017 [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	1,191	1,251
Subsidies to Electro Copper Plating Project, Commenced in 2014 [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	2,445	2,666
Subsidies to Polytetrafluoroethylene Project, Commenced in 2018 [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	123	135
Subsidies to Tahoe-Single Bench Clean, commenced in 2020 [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	1,910	0
Other [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	$ 161	$ 134

LONG-TERM INVESTMENT (Details)

LONG-TERM INVESTMENT (Details) $ / shares in Units, $ in Thousands	Sep. 05, 2019shares	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 27, 2019USD ($)	Sep. 11, 2017USD ($)$ / sharesshares
Classification of Investments [Abstract]
Total		$ 6,015	$ 5,934
Ninebell [Member]
Investments [Abstract]
Percentage of ordinary shares issued						20.00%
Purchase price						$ 1,200
Classification of Investments [Abstract]
Total		1,694	1,538
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%
Number of investors with agreements entered | shares	6
Investment - equity method					$ 109
Classification of Investments [Abstract]
Total		109	107
Hefei Shixi [Member]
Investments [Abstract]
Investment in partnership				$ 4,200
Ownership percentage in partnership				10.00%
Classification of Investments [Abstract]
Total		$ 4,212	$ 4,289

RELATED PARTY BALANCES AND TR_3

RELATED PARTY BALANCES AND TRANSACTIONS (Details) $ / shares in Units, ¥ in Thousands, $ in Thousands	Aug. 14, 2019USD ($)$ / sharesshares	Mar. 30, 2018USD ($)shares	Mar. 14, 2017USD ($)$ / sharesshares	Aug. 31, 2019USD ($)	Mar. 31, 2020USD ($)	Sep. 30, 2019USD ($)$ / sharesshares	Mar. 31, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 09, 2016USD ($)	Dec. 09, 2016CNY (¥)
Related Party Transaction [Abstract]
Purchase of materials					$ 2,211		$ 2,320
Accounts payable					2,793			$ 1,215
ACM Shanghai [Member]
Related Party Transaction [Abstract]
Repayments of notes				$ 1,161
Ninebell Co., Ltd [Member]
Related Party Transaction [Abstract]
Purchase of materials					2,153		2,320
Prepaid expenses					648			348
Accounts payable					2,604			727
Shengyi Semiconductor Technology Co., Ltd [Member]
Related Party Transaction [Abstract]
Purchase of materials					58		$ 0
Accounts payable					$ 189			$ 488
SMC [Member]
Related Party Transaction [Abstract]
Cash delivered as of the close of business									$ 2,981	¥ 20,124
Stock price (in dollars per share) | $ / shares						$ 13.195
Investment repayment period					60 days
Number of shares repurchased/surrender in exchange (in shares) | shares						154,821
Repayments of notes						$ 882
SMC [Member] | Senior Secured Promissory Note [Member]
Related Party Transaction [Abstract]
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]
Related Party Transaction [Abstract]
Shares issued (in shares) | shares			397,502
Shares issued value			$ 2,981
Stock price (in dollars per share) | $ / shares	$ 13.195		$ 7.50
Exercise of common stock warrant issued (in shares) | shares		397,502
Number of shares repurchased/surrender in exchange (in shares) | shares	214,286
Cancellation of options to acquire shares (in shares) | shares	53,571
Cancellation of options to acquire stock, amount	$ 3,403

COMMON STOCK (Details)

COMMON STOCK (Details)	3 Months Ended
	Mar. 31, 2020Vote$ / sharesshares	Mar. 31, 2019shares	Dec. 31, 2019$ / sharesshares
Common Class A [Member]
Class of Stock [Abstract]
Common stock, shares authorized (in shares)	50,000,000		50,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001		$ 0.0001
Number of votes for each share entitled | Vote	1
Common stock, shares issued (in shares)	16,317,346		16,182,151
Common stock, shares outstanding (in shares)	16,317,346		16,182,151
Common Class A [Member] | Common Stock [Member]
Class of Stock [Abstract]
Exercise of common stock warrant issued (in shares)	64,717
Stock issued upon exercise of stock options (in shares)	70,478	66,375
Common Class B [Member]
Class of Stock [Abstract]
Common stock, shares authorized (in shares)	2,409,738		2,409,738
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001		$ 0.0001
Number of votes for each share entitled | Vote	20
Convertible shares in to Class A common stock (in shares)	1
Common stock, shares issued (in shares)	1,862,608		1,862,608
Common stock, shares outstanding (in shares)	1,862,608		1,862,608
Common Class B [Member] | Common Stock [Member]
Class of Stock [Abstract]
Exercise of common stock warrant issued (in shares)	0
Stock issued upon exercise of stock options (in shares)	0	0

REDEEMABLE NON-CONTROLLING IN_3

REDEEMABLE NON-CONTROLLING INTERESTS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Change in Redeemable Non-controlling Interests [Abstract]
Balance	$ 60,162
Net income attributable to redeemable non-controlling interests	258	$ 0
Effect of foreign currency translation loss attributable to redeemable non-controlling interests	(953)
Balance	$ 59,467

STOCK-BASED COMPENSATION, Stock

STOCK-BASED COMPENSATION, Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	$ 689	$ 744
Employee Stock Purchase Plan [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	431	221
Employee Stock Purchase Plan [Member] | ACM Shanghai [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	86	0
Non-Employee Stock Purchase Plan [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	172	523
Cost of Revenue [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	45	30
Sales and Marketing Expense [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	94	34
Research and Development Expense [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	187	86
General and Administrative Expense [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	$ 363	$ 594

STOCK-BASED COMPENSATION, Share

STOCK-BASED COMPENSATION, Share Option Activities (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Weighed Average Remaining Contractual Term [Abstract]
Stock-based compensation expense	$ 689	$ 744
Employee Share Option [Member]
Number of Option Share [Roll Forward]
Outstanding, beginning of period (in shares)	2,994,063
Granted (in shares)	20,000
Exercised (in shares)	(26,032)
Expired (in shares)	0
Forfeited/cancelled (in shares)	(22,000)
Outstanding, end of period (in shares)	2,966,031		2,994,063
Vested and exercisable (in shares)	1,859,052
Weighted Average Grant Date Fair Value [Abstract]
Outstanding at beginning of period (in dollars per share)	$ 2.59
Granted (in dollars per share)	9.11
Exercised (in dollars per share)	1.31
Expired (in dollars per share)	0
Forfeited/cancelled (in dollars per share)	6.46
Outstanding at end of period (in dollars per share)	2.61		$ 2.59
Weighted Average Exercise Price [Abstract]
Outstanding, beginning of period (in dollars per share)	6.77
Granted (in dollars per share)	22.95
Exercised (in dollars per share)	3.60
Expired (in dollars per share)	0
Forfeited/cancelled (in dollars per share)	16.74
Outstanding, end of period (in dollars per share)	$ 6.83		$ 6.77
Weighed Average Remaining Contractual Term [Abstract]
Outstanding weighed average remaining contractual term	6 years 9 months 22 days		7 years 18 days
Stock-based compensation expense	$ 431	221
Unrecognized employee stock-based compensation expense	$ 4,317		$ 4,712
Weighted-average period over which unrecognized compensation is expected to be recognized	1 year 3 months 14 days		1 year 5 months 19 days
Employee Share Option [Member] | ACM Shanghai [Member]
Number of Option Share [Roll Forward]
Outstanding, beginning of period (in shares)	0
Granted (in shares)	5,869,808
Exercised (in shares)	0
Expired (in shares)	0
Forfeited/cancelled (in shares)	(192,308)
Outstanding, end of period (in shares)	5,677,500		0
Vested and exercisable (in shares)	0
Weighted Average Grant Date Fair Value [Abstract]
Outstanding at beginning of period (in dollars per share)	$ 0
Granted (in dollars per share)	0.22
Exercised (in dollars per share)	0
Expired (in dollars per share)	0
Forfeited/cancelled (in dollars per share)	0.23
Outstanding at end of period (in dollars per share)	0.22		$ 0
Weighted Average Exercise Price [Abstract]
Outstanding, beginning of period (in dollars per share)	0
Granted (in dollars per share)	1.87
Exercised (in dollars per share)	0
Expired (in dollars per share)	0
Forfeited/cancelled (in dollars per share)	1.87
Outstanding, end of period (in dollars per share)	$ 1.87		$ 0
Weighed Average Remaining Contractual Term [Abstract]
Outstanding weighed average remaining contractual term	4 years 3 months 4 days		0 years
Stock-based compensation expense	$ 86	0
Non-Employee Stock Option [Member]
Number of Option Share [Roll Forward]
Outstanding, beginning of period (in shares)	1,101,613
Granted (in shares)	20,000
Exercised (in shares)	(44,446)
Expired (in shares)	0
Forfeited/cancelled (in shares)	0
Outstanding, end of period (in shares)	1,077,167		1,101,613
Vested and exercisable (in shares)	1,007,076
Weighted Average Grant Date Fair Value [Abstract]
Outstanding at beginning of period (in dollars per share)	$ 0.82
Granted (in dollars per share)	10.29
Exercised (in dollars per share)	0.44
Expired (in dollars per share)	0
Forfeited/cancelled (in dollars per share)	0
Outstanding at end of period (in dollars per share)	1.01		$ 0.82
Weighted Average Exercise Price [Abstract]
Outstanding, beginning of period (in dollars per share)	2.69
Granted (in dollars per share)	25.60
Exercised (in dollars per share)	1.82
Expired (in dollars per share)	0
Forfeited/cancelled (in dollars per share)	0
Outstanding, end of period (in dollars per share)	$ 3.15		$ 2.69
Weighed Average Remaining Contractual Term [Abstract]
Outstanding weighed average remaining contractual term	5 years 9 months		5 years 10 months 6 days
Stock-based compensation expense	$ 172	$ 523
Unrecognized employee stock-based compensation expense	$ 419		$ 406
Weighted-average period over which unrecognized compensation is expected to be recognized	2 months 19 days		2 months 23 days
Non-Employee Stock Option [Member] | ACM Shanghai [Member]
Weighed Average Remaining Contractual Term [Abstract]
Unrecognized employee stock-based compensation expense	$ 1,106
Weighted-average period over which unrecognized compensation is expected to be recognized	3 years 3 months 4 days

INCOME TAXES (Details)

INCOME TAXES (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)Subsidiary	Mar. 31, 2019USD ($)
Income Taxes [Abstract]
Statutory U.S federal income tax rate	21.00%
Income tax (benefit) expense	$ 304	$ 119
Unrecognized tax benefits	44
Interest or penalties	0
Current [Abstract]
U.S. federal	(10)	0
U.S. state	0	0
Foreign	(257)	0
Total current tax expense	(267)	0
Deferred [Abstract]
U.S. federal	(28)	0
U.S. state	0	0
Foreign	(9)	(119)
Total deferred tax benefit	(37)	(119)
Total income tax expense	$ (304)	$ (119)
China [Member]
Deferred [Abstract]
Number of subsidiaries | Subsidiary	2
Effective period of preferential income tax rate	3 years
China [Member] | Minimum [Member]
Income Taxes [Abstract]
Foreign corporate tax rate	15.00%
China [Member] | Maximum [Member]
Income Taxes [Abstract]
Foreign corporate tax rate	25.00%

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	Mar. 31, 2020USD ($)
COMMITMENTS AND CONTINGENCIES [Abstract]
Commitments	$ 636