Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2017	Dec. 05, 2017
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q3
Trading Symbol	ACMR
Entity Registrant Name	ACM RESEARCH, INC.
Entity Central Index Key	0001680062
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Class A Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		12,935,546
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		2,409,738

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 17,074	$ 10,119
Restricted cash	433	0
Accounts receivable, less allowance for doubtful accounts of $0 and $0 at September 30, 2017 and December 31, 2016, respectively (note 3)	15,784	16,026
Loans receivable - related party (note 12)	946
Other receivables	2,017	1,763
Inventory (note 4)	18,077	11,666
Prepaid expenses	801	720
Other current assets	890	53
Total current assets	56,022	40,347
Property, plant and equipment, net (note 5)	2,346	2,262
Intangible assets, net	35	17
Deferred tax assets (note 17)	1,433	1,841
Investment in equity method affiliates (note 11)	1,220
Total assets	61,056	44,467
Current liabilities:
Short-term borrowings (note 6)	3,472	4,761
Notes payable	11	11
Investors' deposit (note 8)		2,902
Warrant liability (note 9)	3,033
Accounts payable (including amounts due to a related party of $1,925 and $508 at September 30, 2017 and December 31, 2016, respectively (note 12))	8,667	5,173
Advances from customers	75	215
Income tax payable	44	44
Other payables and accrued expenses (including amounts due to a related-party of $2,024 (unaudited) and $1,883 as of September 30, 2017 and December 31, 2016, respectively (note 12) (note 7))	5,264	3,963
Total current liabilities	20,566	17,069
Other long-term liabilities (note 10)	6,682	6,879
Total liabilities	27,248	23,948
Commitments and contingencies (Note 18)
Redeemable convertible preferred stock, par value $0.0001:
Redeemable convertible preferred stock	23,834	18,034
Stockholders' equity (deficit):
Additional paid in capital	19,244	7,620
Accumulated deficit	(13,344)	(9,643)
Accumulated other comprehensive loss	(109)	(413)
Total ACM Research, Inc. stockholders' equity (deficit)	5,793	(2,434)
Non-controlling interests	4,181	4,919
Total stockholders' equity	9,974	2,485
Total liabilities, redeemable convertible preferred stock and stockholders' equity	61,056	44,467
Series A Convertible Preferred Stock [Member]
Redeemable convertible preferred stock, par value $0.0001:
Redeemable convertible preferred stock	288	288
Series B Convertible Preferred Stock [Member]
Redeemable convertible preferred stock, par value $0.0001:
Redeemable convertible preferred stock	1,572	1,572
Series C Convertible Preferred Stock [Member]
Redeemable convertible preferred stock, par value $0.0001:
Redeemable convertible preferred stock	2,041	2,041
Series D Convertible Preferred Stock [Member]
Redeemable convertible preferred stock, par value $0.0001:
Redeemable convertible preferred stock	4,975	4,975
Series E Convertible Preferred Stock [Member]
Redeemable convertible preferred stock, par value $0.0001:
Redeemable convertible preferred stock	5,800
Series F Convertible Preferred Stock [Member]
Redeemable convertible preferred stock, par value $0.0001:
Redeemable convertible preferred stock	9,158	9,158
Class A Common Stock [Member]
Stockholders' equity (deficit):
Common stock	1	1
Common Class B [Member]
Stockholders' equity (deficit):
Common stock	1	$ 1
Pro Forma [Member]
Current assets:
Cash and cash equivalents	17,074
Restricted cash	433
Accounts receivable, less allowance for doubtful accounts of $0 and $0 at September 30, 2017 and December 31, 2016, respectively (note 3)	15,784
Loans receivable - related party (note 12)	946
Other receivables	2,017
Inventory (note 4)	18,077
Prepaid expenses	801
Other current assets	890
Total current assets	56,022
Property, plant and equipment, net (note 5)	2,346
Intangible assets, net	35
Deferred tax assets (note 17)	1,433
Investment in equity method affiliates (note 11)	1,220
Total assets	61,056
Current liabilities:
Short-term borrowings (note 6)	3,472
Notes payable	11
Warrant liability (note 9)	3,033
Accounts payable (including amounts due to a related party of $1,925 and $508 at September 30, 2017 and December 31, 2016, respectively (note 12))	8,667
Advances from customers	75
Income tax payable	44
Other payables and accrued expenses (including amounts due to a related-party of $2,024 (unaudited) and $1,883 as of September 30, 2017 and December 31, 2016, respectively (note 12) (note 7))	5,264
Total current liabilities	20,566
Other long-term liabilities (note 10)	6,682
Total liabilities	27,248
Commitments and contingencies (Note 18)
Stockholders' equity (deficit):
Additional paid in capital	43,078
Accumulated deficit	(13,344)
Accumulated other comprehensive loss	(109)
Total ACM Research, Inc. stockholders' equity (deficit)	29,627
Non-controlling interests	4,181
Total stockholders' equity	33,808
Total liabilities, redeemable convertible preferred stock and stockholders' equity	61,056
Pro Forma [Member] \| Class A Common Stock [Member]
Stockholders' equity (deficit):
Common stock	1
Pro Forma [Member] \| Common Class B [Member]
Stockholders' equity (deficit):
Common stock	$ 1

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Accounts receivable, allowance for doubtful accounts	$ 0	$ 0
Accounts payable, Due to a related party	1,925	508
Other payables and accrued expenses, due to a related-party	$ 2,024	$ 1,883
Redeemable convertible preferred stock, par value	$ 0.0001	$ 0.0001
Redeemable preferred stock, shares authorized	22,696,467
Series A Convertible Preferred Stock [Member]
Redeemable preferred stock, shares authorized	385,000	385,000
Redeemable preferred stock, shares issued	385,000	385,000
Redeemable preferred stock, shares outstanding	385,000	385,000
Redeemable preferred stock, liquidation value	$ 308	$ 308
Series B Convertible Preferred Stock [Member]
Redeemable preferred stock, shares authorized	1,572,000	1,572,000
Redeemable preferred stock, shares issued	1,572,000	1,572,000
Redeemable preferred stock, shares outstanding	1,572,000	1,572,000
Redeemable preferred stock, liquidation value	$ 1,572
Series C Convertible Preferred Stock [Member]
Redeemable preferred stock, shares authorized	1,360,962	1,360,962
Redeemable preferred stock, shares issued	1,360,962	1,360,962
Redeemable preferred stock, shares outstanding	1,360,962	1,360,962
Redeemable preferred stock, liquidation value	$ 2,041	$ 2,041
Series D Convertible Preferred Stock [Member]
Redeemable preferred stock, shares authorized	2,659,975	2,659,975
Redeemable preferred stock, shares issued	1,326,642	1,326,642
Redeemable preferred stock, shares outstanding	1,326,642	1,326,642
Redeemable preferred stock, liquidation value	$ 4,975	$ 4,975
Series E Convertible Preferred Stock [Member]
Redeemable preferred stock, shares authorized	10,718,530	10,718,530
Redeemable preferred stock, shares issued	4,998,508	0
Redeemable preferred stock, shares outstanding	4,998,508	0
Redeemable preferred stock, liquidation value	$ 4,999
Series F Convertible Preferred Stock [Member]
Redeemable preferred stock, shares authorized	6,000,000	6,000,000
Redeemable preferred stock, shares issued	3,663,254	3,663,254
Redeemable preferred stock, shares outstanding	3,663,254	3,663,254
Redeemable preferred stock, liquidation value	$ 9,158	$ 9,158
Class A Common Stock [Member]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	4,741,635	2,228,740
Common stock, shares outstanding	4,741,635	2,228,740
Class A Common Stock [Member] \| Pro Forma [Member]
Common stock, par value	$ 0.0001
Common stock, shares authorized	100,000,000
Common stock, shares issued	9,369,212
Common stock, shares outstanding	9,369,212
Common Class B [Member]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	7,303,533	7,303,533
Common stock, shares issued	2,409,738	2,409,738
Common stock, shares outstanding	2,409,738	2,409,738
Common Class B [Member] \| Pro Forma [Member]
Common stock, par value	$ 0.0001
Common stock, shares authorized	7,303,533
Common stock, shares issued	2,409,738
Common stock, shares outstanding	2,409,738

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Revenue	$ 4,891	$ 4,904	$ 19,314	$ 13,026
Cost of revenue	2,692	1,989	11,262	7,281
Gross profit	2,199	2,915	8,052	5,745
Operating expenses, net:
Sales and marketing	1,036	709	3,619	2,527
Research and development	1,209	813	3,076	2,299
General and administrative	1,264	605	4,422	1,694
Total operating expenses, net	3,509	2,127	11,117	6,520
Income (loss) from operations	(1,310)	788	(3,065)	(775)
Interest income	2	7	7	13
Interest expense	(33)	(67)	(197)	(118)
Equity in net income of affiliates	20		20
Non-operating income (expense), net	(239)	(35)	(531)	471
Income (loss) before income taxes	(1,560)	693	(3,766)	(409)
Income tax benefit (expense) (note 17)	278	(132)	(471)	(59)
Net income (loss)	(1,282)	561	(4,237)	(468)
Less: Net income (loss) attributable to non-controlling interests	(327)	199	(535)	(277)
Net income (loss) attributable to ACM Research, Inc.	(955)	362	(3,702)	(191)
Comprehensive income (loss):
Net income (loss)	(1,282)	561	(4,237)	(468)
Foreign currency translation adjustment	228	(66)	492	(199)
Comprehensive income (loss)	(1,054)	495	(3,745)	(667)
Less: Comprehensive income (loss) attributable to non-controlling interests	(237)	175	(347)	(351)
Total comprehensive income (loss) attributable to ACM Research, Inc.	$ (817)	$ 320	$ (3,398)	$ (316)
Net income (loss) per common shares (note 2)
Basic	$ (0.17)	$ 0.07	$ (0.72)	$ (0.09)
Diluted	$ (0.17)	$ 0.05	$ (0.72)	$ (0.09)
Weighted average common stocks outstanding used in computing per share amounts (note 2)
Basic	5,581,637	2,108,324	5,148,255	2,077,115
Diluted	5,581,637	3,372,505	5,148,255	2,077,115

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net loss	$ (4,237)	$ (468)
Adjustments to reconcile net loss from operations to net cash provided by (used in) operating activities:
Depreciation and amortization	183	134
Undistributed earnings from investments in equity method affiliates	(20)
Loss on disposals of fixed assets, intangible assets and other long-term assets		3
Deferred income taxes	491	58
Stock-based compensation	1,692	193
Net changes in operating assets and liabilities:
Restricted Cash	(433)
Accounts receivable	966	7,828
Other receivables	(170)	11
Inventory	(5,933)	(1,925)
Prepaid expenses	(20)	430
Other current assets	(836)	(20)
Accounts payable	3,242	1,000
Advances from customers	(180)	(4,487)
Other payables and accrued expenses	1,099	(307)
Other long-term liabilities	(505)	519
Net cash provided by (used in) operating activities	(4,661)	2,969
Cash flows from investing activities:
Purchase of property and equipment	(149)	(177)
Purchase of intangible assets	(37)	(22)
Proceed from disposal of property and equipment		8
Loan to related party	(946)
Purchase of non-controlling interest	(6,154)
Investments in unconsolidated equity method affiliates	(1,200)
Net cash used in investing activities	(8,486)	(191)
Cash flows from financing activities:
Proceeds from short-term borrowings	8,153	3,795
Repayments of short-term borrowings	(9,643)	(7,398)
Proceeds from stock option exercise to common stock	396	53
Proceed from issuance of Series E convertible preferred stock	5,800
Proceeds from issuance of Common Stock	15,300
Investor deposits for Series F convertible preferred stock		4,328
Net cash provided by financing activities	20,006	778
Effect of exchange rate changes on cash and cash equivalents	96	(114)
Net increase in cash and cash equivalents	6,955	3,442
Cash and cash equivalents at beginning of period	10,119	4,401
Cash and cash equivalents at end of period	17,074	7,843
Supplemental disclosure of cash flow information:
Interest paid	196	99
Income taxes paid	$ 0	$ 0

Description of Business	9 Months Ended
Description of Business	Sep. 30, 2017
Accounting Policies [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, under the brand name “Ultra C,” lines of equipment 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 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. The Company also offers a range of custom-made equipment, including cleaners, coaters and developers, to back-end wafer assembly and packaging factories, principally in the PRC. In 2011 ACM Shanghai formed a wholly owned subsidiary in the PRC, ACM Research (Wuxi), Inc. (“ACM Wuxi”), to manage sales and service operations. In November 2016 ACM redomesticated from California to Delaware pursuant to a merger in which ACM Research, Inc., a California corporation, was merged into a newly formed, wholly owned Delaware subsidiary, also named ACM Research, Inc. In June 2017 ACM formed a wholly owned subsidiary in Hong Kong, CleanChip Technologies Limited (“CleanChip”), to act on the Company’s behalf in Asian markets outside the PRC by, for example, serving as a trading partner between ACM Shanghai and its customers, procuring raw materials and components, performing sales and marketing activities, and making strategic investments. In August 2017 ACM purchased 18.77% of ACM Shanghai’s equity interests held by Shanghai Science and Technology Venture Capital Co., Ltd. (“SSTVC”). As of September 30, 2017, and December 31, 2016, respectively, ACM owned 81.64% and 62.87% of the outstanding equity interests of ACM Shanghai, and indirectly through ACM Shanghai, owned 81.64% and 62.87% of the outstanding equity interests of ACM Wuxi, respectively. In August 2017 ACM entered into securities purchase agreements pursuant to which ACM proposes to acquire the remaining outstanding non-controlling equity interests of ACM Shanghai (see note 14). On September 13, 2017, ACM effectuated a 1-for-3 reverse stock split (the “Reverse Split”) of Class A and Class B common stock. Unless otherwise indicated, all share numbers, per share amount, share prices, exercise prices and conversion rates set forth in those notes and the accompanying condensed consolidated financial statements have been adjusted retrospectively to reflect the Reverse Split.

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2017

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

NOTE 2 – SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation and Principles of 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”). The consolidated accounts include ACM and its subsidiaries, ACM Shanghai, ACM Wuxi and CleanChip. 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 balance sheet as of September 30, 2017, the condensed consolidated statements of comprehensive income (loss) for the three and nine months ended September 30, 2017 and 2016, and the condensed consolidated statements of cash flows for the nine months ended September 30, 2017 and 2016 are unaudited. In the opinion of management, the unaudited condensed consolidated financial statements of the Company reflect all adjustments, which 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 September 30, 2017 and the results of operations for the three and nine months ended September 30, 2017 are not necessarily indicative of the results to be expected for any future period. The 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, 2016.

Unaudited Pro Forma Balance Sheet

The unaudited pro forma condensed consolidated balance sheet as of September 30, 2017 gives effect to the automatic conversion of all of the Company’s outstanding redeemable convertible preferred stock into shares of Class A common stock, which occurred upon completion of an IPO of common stock on November 7, 2017.

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 revenues and expenses during the reported period in the condensed consolidated financial statements and accompanying notes. The Company’s significant accounting estimates and assumptions include, but are not limited to, those used for 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.

Restricted Cash

Restricted cash is money that is reserved for a specific purpose and therefore not available for immediate or general business use. At September 30, 2017 and December 31, 2016, restricted cash was $433 and $0, respectively. The restricted cash represents a deposit for a letter of credit issued for international purchase.

Deferred Initial Public Offering (“IPO”) Costs

Direct costs incurred by the Company attributable to its IPO of Class A common stock in the United States were deferred and recorded in other current assets and will be offset against the gross proceeds received from the IPO. At September 30, 2017 and December 31, 2016, deferred IPO costs were $819 and $41, respectively.

Basic and Diluted Net Income (Loss) per Common Share

Basic and diluted net income (loss) per common share is calculated as follows:


	Three Months Ended September 30,					Nine Months Ended September 30,
	2017			2016		2017			2016
Numerator:
Net income (loss)	$	(1,282	)	$	561	$	(4,237	)	$	(468	)
Net income (loss) attributable to non-controlling interest		(327	)		199		(535	)		(277	)
Net income allocated to participating securities		—			205		—			—

Net income (loss) available to common stockholders, basic and diluted	$	(955	)	$	157	$	(3,702	)	$	(191	)

Denominator:
Weighted average shares outstanding, basic		5,581,637			2,108,324		5,148,255			2,077,115
Effect of dilutive securities		—			1,264,181		—			—

Weighted average shares outstanding, diluted		5,581,637			3,372,505		5,148,255			2,077,115

Net income (loss) per common share:
Basic	$	(0.17	)	$	0.07	$	(0.72	)	$	(0.09	)
Diluted	$	(0.17	)	$	0.05	$	(0.72	)	$	(0.09	)

Basic and diluted net income (loss) per common share is presented using the two-class method, which allocates undistributed earnings to common stock and any participating securities according to dividend rights and participation rights on a proportionate basis. Under the two-class method, basic net income (loss) per common share is computed by dividing the sum of distributed and undistributed earnings attributable to common stockholders by the weighted average number of shares of common stock outstanding during the period. Shares of ACM’s Series A, B, C, D, E and F convertible preferred stock are participating securities, as the holders are entitled to participate in and receive the same dividends as may be declared for common stockholders on a pro-rata, if-converted basis.

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 for the three and nine months ended September 30, 2017 and 2016, the net income (loss) 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 consolidated statements of operations and comprehensive income (loss) and in the above computation of net income (loss) per common share.

Diluted net income (loss) per common share reflects the potential dilution from securities that could share in ACM’s earnings. ACM’s potential dilutive securities consist of convertible preferred stocks, stock options and warrants for the three and nine months ended September 30, 2017 and 2016. Certain potential dilutive securities were excluded from the net income (loss) per share calculation because the impact would be anti-dilutive.

Fair Value of Financial Instruments

Under the authoritative guidance of the Financial Accounting Standards Board (“FASB”) on fair value measurements, fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. In determining the fair value, the Company uses various methods including market, income and cost approaches. Based on these approaches, the Company often utilizes certain assumptions that market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs can be readily observable, market corroborated or generally unobservable inputs. The Company uses valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. Based on observability of the inputs used in the valuation techniques, the Company is required to provide the following information according to the fair value hierarchy. The fair value hierarchy ranks the quality and reliability of the information used to determine fair values. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three categories:


Level 1:		Valuations for assets and liabilities traded in active exchange markets. Valuations are obtained from readily available pricing sources for market transactions involving identical assets or liabilities.

Level 2:		Valuations for assets and liabilities traded in less active dealer or broker markets. Valuations are obtained from third party pricing services for identical or similar assets or liabilities.

Level 3:		Valuations for assets and liabilities that are derived from other valuation methodologies, including option pricing models, discounted cash flow models and similar techniques, and not based on market exchange, dealer or broker traded transactions. Level 3 valuations incorporate certain unobservable assumptions and projections in determining the fair value assigned to such assets.

All transfers between fair value hierarchy levels are recognized by the Company at the end of each reporting period. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. The inputs or methodology used for valuing financial instruments are not necessarily an indication of the risks associated with investment in those instruments.

Fair Value Measured or Disclosed on a Recurring Basis

Short-term borrowings—Interest rates under the borrowing agreements with the lending parties were determined based on the prevailing interest rates in the market. The Company classifies the valuation techniques that use these inputs as Level 2 fair value measurement.

Warrant liability—The fair value of the warrant liability derives from the Black-Scholes valuation model which incorporates certain unobservable assumptions (note 9). The Company classifies the valuation techniques that use these inputs as Level 3 fair value measurement.

Other financial items for disclosure purpose—The fair value of other financial items of the Company for disclosure purpose, including cash and cash equivalents, accounts receivable, other receivables, prepaid expenses, other current assets, notes payable, investors’ deposits, accounts payable, advances from customers, income taxes payable, and other payables and accrued expenses, approximate their carrying value due to their short-term nature.

As of September 30, 2017 and December 31, 2016, information about inputs into the fair value measurement of the Company’s liabilities that are measured and recorded at fair value on a recurring basis in periods subsequent to their initial recognition is as follows:


	Fair Value Measurement at Reporting Date Using
	Quoted Prices in Active Markets for Identical Liabilities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
As of September 30:
Liabilities:
Short-term borrowings	$	—	$	3,472	$	—	$	3,472
Warrant liability		—		—		3,033		3,033

		—		3,472		3,033		6,505

As of December 31, 2016:
Liabilities:
Short-term borrowings	$	—	$	4,761	$	—	$	4,761

Fair Value Measured on a Non-Recurring Basis

The Company reviews long-lived assets for impairment annually or more frequently if events or changes in circumstances indicate the possibility of impairment. Long-lived assets are measured at fair value on a nonrecurring basis when there is an indicator of impairment, and they are recorded at fair value only when impairment is recognized. In determining the fair value, the Company used projections of cash flows directly associated with, and which are expected to arise as a direct result of, the use and eventual disposition of the assets. This approach required significant judgments including the Company’s projected net cash flows, which were derived using the most recent available estimate for the reporting unit containing the assets tested. Several key assumptions included periods of operation, projections of product pricing, production levels, product costs, market supply and demand, and inflation.

Recent Accounting Pronouncements

Accounting Pronouncements Recently Adopted in the Consolidated Financial Statements for the Nine Months Ended September 30, 2017

In April 2016, the FASB issued Accounting Standards Update (“ASU”) No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, which simplifies several aspects of the accounting for employee stock-based payment transactions. The areas for simplification in ASU No. 2016-09 include the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The amendments in this ASU were effective for annual periods beginning after December 15, 2016 and interim periods within those annual periods. The adoption of ASU No. 2016-09 did not have a material impact on the Company’s consolidated financial statements.

In November 2015, the FASB issued ASU No. 2015-17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes. Topic 740, Income Taxes, requires an entity to separate deferred income tax liabilities and assets into current and noncurrent amounts in a classified statement of financial position. Deferred tax liabilities and assets are classified as current or noncurrent based on the classification of the related asset or liability for financial reporting. Deferred tax liabilities and assets that are not related to an asset or liability for financial reporting are classified according to the expected reversal date of the temporary difference. To simplify the presentation of deferred income taxes, the amendments in ASU No. 2015-17 require that deferred income tax liabilities and assets be classified as noncurrent in a classified statement of financial position. For public business entities, the amendments in this update are effective for financial statements issued for annual periods beginning after December 15, 2016, and interim periods within those annual periods. The adoption of ASU No. 2015-17 did not have a material impact on the Company’s consolidated financial statements.

In July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory. The amendments in this update require an entity to measure inventory within the scope of ASU No. 2015-11 (the amendments in ASU No. 2015-11 do not apply to inventory that is measured using last-in, first-out or the retail inventory method. The amendments apply to all other inventory, which includes inventory that is measured using first-in, first-out or average cost) at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. Subsequent measurement is uncharged for inventory measured using last-in, first-out or the retail inventory method. The amendments in ASU No. 2015-11 more closely align the measurement of inventory in GAAP with the measurement of inventory in International Financial Reporting Standards. ASU No. 2015-11 is effective for public business entities for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The amendments in ASU No. 2015-11 should be applied prospectively with earlier application permitted as of the beginning of an interim or annual reporting period. The adoption of ASU No. 2015-11 did not have a material impact on the Company’s consolidated financial statements. The relevant descriptions have been included in the inventory accounting policy.

In August 2014, the FASB issued ASU No. 2014-15, Presentation of Financial Statements—Going Concern. The amendments in this update require management to evaluate whether there are conditions and events that raise substantial doubt about an entity’s ability to continue as a going concern for both annual and interim reporting. The guidance is effective for the Company for the annual period ended after December 15, 2016 and interim periods thereafter. Management performed an evaluation of the Company’s ability to fund operations and to continue as a going concern according to the FASB Accounting Standards Codification (“ASC”) Topic 205-40, Presentation of Financial Statements—Going Concern. The adoption of ASU No. 2014-15 did not have a material impact on the Company’s consolidated financial statements.

Recent Accounting Pronouncements Not Yet Adopted

In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815): (Part I) Accounting for Certain Financial Instruments with Down Round Features, (Part II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception, which addresses the complexity of accounting for certain financial instruments with down round features. Down round features are features of certain equity-linked instruments (or embedded features) that result in the strike price being reduced on the basis of the pricing of future equity offerings. Current accounting guidance creates cost and complexity for entities that issue financial instruments (such as warrants and convertible instruments) with down round features that require fair value measurement of the entire instrument or conversion option. For public business entities, the amendments in Part I of this Update are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. For all other entities, the amendments in Part I of this Update are effective for fiscal years beginning after December 15, 2019, and interim periods within fiscal years beginning after December 15, 2020. The Company is evaluating the impact of the adoption of ASU No. 2017-11 on its consolidated financial statements.

In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting, which provides guidance on determining which changes to the terms and conditions of share-based payment awards require an entity to apply modification accounting under Topic 718. The amendments in this ASU are effective for all entities for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted, including adoption in any interim period, for (1) public business entities for reporting periods for which financial statements have not yet been issued and (2) all other entities for reporting periods for which financial statements have not yet been made available for issuance. The amendments in this ASU should be applied prospectively to an award modified on or after the adoption date. The Company does not expect the adoption of ASU No. 2017-09 to have a material impact on its consolidated financial statements.

In February 2017, the FASB issued ASU No. 2017-05, Other Income—Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets, which clarifies the scope of nonfinancial asset guidance in Subtopic 610-20. This ASU also clarifies that derecognition of all businesses and nonprofit activities (except those related to conveyances of oil and gas mineral rights or contracts with customers) should be accounted for in accordance with the derecognition and deconsolidation guidance in Subtopic 810-10. The amendments in this ASU also provide guidance on the accounting for so-called “partial sales” of nonfinancial assets within the scope of Subtopic 610-20 and contributions of nonfinancial assets to a joint venture or other noncontrolled investee. The amendments in this ASU are effective for annual reporting reports beginning after December 15, 2017, including interim reporting periods within that reporting period. The Company does not expect the adoption of ASU No. 2017-05 to have a material impact on its consolidated financial statements.

In January 2017, the FASB issued ASU No. 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, which removes Step 2 from the goodwill impairment test. An entity will apply a one-step quantitative test and record the amount of goodwill impairment as the excess of a reporting unit’s carrying amount over its fair value, not to exceed the total amount of goodwill allocated to the reporting unit. The new guidance does not amend the optional qualitative assessment of goodwill impairment. A business entity that is a U.S. Securities and Exchange Commission filer must adopt the amendments in this ASU for its annual or any interim goodwill impairment test in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company is evaluating the impact of the adoption of ASU 2017-04 on its consolidated financial statements.

In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash, which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The amendments in this ASU do not provide a definition of restricted cash or restricted cash equivalents. The amendments in this ASU are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The Company does not expect the adoption of ASU No. 2016-18 to have a material impact on its consolidated financial statements.

In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments, which addresses the following cash flow issues: (1) debt prepayment or debt extinguishment costs; (2) settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing; (3) contingent consideration payments made after a business combination; (4) proceeds from the settlement of insurance claims; (5) proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies; (6) distributions received from equity method investees; (7) beneficial interests in securitization transactions; and (8) separately identifiable cash flows and application of the predominance principle. The amendments in this ASU are effective for public business entities for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years and are effective for all other entities for fiscal years beginning after December 15, 2018 and interim periods within fiscal years beginning after December 15, 2019. Early adoption is permitted, including adoption in an interim period. The Company is evaluating the impact of the adoption of ASU No. 2016-15 on its consolidated financial statements.

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The amendments in this update create Topic 842, Leases, and supersede the leases requirements in Topic 840, Leases. Topic 842 specifies the accounting for leases. The objective of Topic 842 is to establish the principles that lessees and lessors shall apply to report useful information to users of financial statements about the amount, timing, and uncertainty of cash flows arising from a lease. The main difference between Topic 842 and Topic 840 is the recognition of lease assets and lease liabilities for those leases classified as operating leases under Topic 840. Topic 842 retains a distinction between finance leases and operating leases. The classification criteria for distinguishing between finance leases and operating leases are substantially similar to the classification criteria for distinguishing between capital leases and operating leases in the previous leases guidance. The result of retaining a distinction between finance leases and operating leases is that under the lessee accounting model in Topic 842, the effect of leases in the statement of comprehensive income and the statement of cash flows is largely unchanged from previous GAAP. The amendments in ASU No. 2016-02 are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years for public business entities. Early application of the amendments in ASU No. 2016-02 is permitted. The Company is in the process of evaluating the impact of the adoption of ASU No. 2016-02 on its consolidated financial statements.

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). ASU No. 2014-09 supersedes the revenue recognition requirements in “Revenue Recognition (Topic 605)”, and requires entities to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. The FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date in August 2015. The amendments in ASU No. 2015-14 defer the effective date of ASU No. 2014-09. Public business entities, certain not-for-profit entities, and certain employee benefit plans should apply the guidance in ASU No. 2014-09 to annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. Earlier adoption is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. Further to ASU No. 2014-09 and ASU No. 2015-14, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) in March 2016, ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing in April 2016, ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients, and ASU No. 2016-20, Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers, respectively. The amendments in ASU No. 2016-08 clarify the implementation guidance on principal versus agent considerations, including indicators to assist an entity in determining whether it controls a specified good or service before it is transferred to the customers. ASU No. 2016-10 clarifies guideline related to identifying performance obligations and licensing implementation guidance contained in the new revenue recognition standard. The updates in ASU No. 2016-10 include targeted improvements based on input the FASB received from the Transition Resource Group for Revenue Recognition and other stakeholders. It seeks to proactively address areas in which diversity in practice potentially could arise, as well as to reduce the cost and complexity of applying certain aspects of the guidance both at implementation and on an ongoing basis. ASU No. 2016-12 addresses narrow-scope improvements to the guidance on collectability, non-cash consideration, and completed contracts at transition. Additionally, the amendments in this ASU provide a practical expedient for contract modifications at transition and an accounting policy election related to the presentation of sales taxes and other similar taxes collected from customers. The amendments in ASU No. 2016-20 represents changes to make minor corrections or minor improvements to the Codification that are not expected to have a significant effect on current accounting practice or create a significant administrative cost to most entities. The effective date and transition requirements for ASU No. 2016-08, ASU No. 2016-10, ASU No. 2016-12 and ASU No. 2016-20 are the same as ASU No. 2014-09. The Company will adopt ASU No. 2014-09, ASU No. 2016-08, ASU No. 2016-10, ASU No. 2016-12 and ASU No. 2016-20 at January 1, 2018 if the IPO is completed by December 31, 2017. The Company is in the process of assessing the potential effects of these ASUs on its consolidated financial statements, business processes, systems and controls. While the assessment process is ongoing, the Company anticipates adopting ASC Topic 606, Revenue from Contracts with Customers, using the modified retrospective transition approach. Under this approach, ASC Topic 606 would apply to all new contracts initiated on or after January 1, 2018. For existing contracts that have remaining obligations as of January 1, 2018, any difference between the recognition criteria in these ASUs and the Company’s current revenue recognition practices would be recognized using a cumulative effect adjustment to the opening balance of accumulated deficit. The Company does not expect the adoption of these ASUs to have a material impact on its consolidated financial statements.

Accounts Receivable

9 Months Ended

Sep. 30, 2017

Receivables [Abstract]

Accounts Receivable

NOTE 3 – ACCOUNTS RECEIVABLE

At September 30, 2017 and December 31, 2016, accounts receivable consisted of the following:


	September 30, 2017		December 31, 2016
Accounts receivable	$	15,784	$	16,026
Less: Allowance for doubtful accounts		—		—

Total	$	15,784	$	16,026

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 September 30, 2017 or December 31, 2016. At September 30, 2017 and December 31, 2016, no accounts receivable were pledged as collateral for borrowings from financial institutions.

- Definition

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.

+ References + Details

Inventory

9 Months Ended

Sep. 30, 2017

Inventory Disclosure [Abstract]

Inventory

NOTE 4 – INVENTORY

At September 30, 2017 and December 31, 2016, inventory consisted of the following:


	September 30, 2017		December 31, 2016
Raw materials	$	7,343	$	7,698
Work in process		3,425		1,260
Finished goods		7,309		2,708

Total inventory, gross		18,077		11,666
Inventory reserve		—		—

Total inventory, net	$	18,077	$	11,666

At September 30, 2017 and December 31, 2016, the Company did not have an inventory reserve and no inventory was pledged as collateral for borrowings from financial institutions.

Property, Plant and Equipment, Net

9 Months Ended

Sep. 30, 2017

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment, Net

NOTE 5 – PROPERTY, PLANT AND EQUIPMENT, NET

At September 30, 2017 and December 31, 2016, property, plant and equipment consisted of the following:


	September 30, 2017			December 31 2016
Manufacturing equipment	$	9,515		$	8,566
Office equipment		458			410
Transportation equipment		200			191
Leasehold improvement		243			224

Total cost		10,416			9,391
Less: Total accumulated depreciation		(8,070	)		(7,562	)
Construction in progress		—			433

Total property, plant and equipment, net	$	2,346		$	2,262

Depreciation expense was $55 and $31 for the three months ended September 30, 2017 and 2016, respectively, and $162 and $119 for the nine months ended September 30, 2017 and 2016, respectively.

Short-Term Borrowings

9 Months Ended

Sep. 30, 2017

Debt Disclosure [Abstract]

Short-Term Borrowings

NOTE 6 – SHORT-TERM BORROWINGS

At September 30, 2017 and December 31, 2016, short-term borrowing consisted of the following:


	September 30, 2017		December 31, 2016
Borrowings from Bank of China, due on February 10, 2017 with annual interest rate of 4.8%, secured by certain of the Company’s intellectual property and fully repaid on February 13, 2017	$	—	$	1,222
Borrowings from Bank of Shanghai Pudong Branch, due on June 24, 2017 with an annual interest rate of 5.66%, guaranteed by the Company’s CEO and fully repaid on June 25, 2017		—		281
Line of credit up to $3,605 from Bank of Shanghai Pudong Branch, due on July 3, 2017 with an annual interest rate of 5.66%, guaranteed by the Company’s CEO and fully repaid on June 7, 2017		—		1,455
Line of credit up to $3,670 from Bank of Shanghai Pudong Branch, due on July 3, 2017 with an annual interest rate of 3.2%, guaranteed by the Company’s CEO and fully repaid on May 18, 2017		—		1,803
Line of credit up to $4,521 from Bank of China Pudong Branch, due on March 5, 2018 with annual interest rate of 5.69%, secured by certain of the Company’s intellectual property		2,185		—
Line of credit up to $3,767 from Bank of Shanghai Pudong Branch, due on September 22,2018 with an annual interest rate of 5.66%, guaranteed by the Company’s CEO		663		—
Line of credit up to $3,767 from Bank of Shanghai Pudong Branch, due on September 23,2018 with an annual interest rate of 5.66%, guaranteed by the Company’s CEO		624		—

Total	$	3,472	$	4,761

Interest expense related to short-term borrowings amounted to $33 and $39 for the three months ended September 30, 2017 and 2016, respectively, and $196 and $150 for the nine months ended September 30, 2017 and 2016, respectively.

Other Payable and Accrued Expenses

9 Months Ended

Sep. 30, 2017

Payables and Accruals [Abstract]

Other Payable and Accrued Expenses

NOTE 7 – OTHER PAYABLE AND ACCRUED EXPENSES

At September 30, 2017 and December 31, 2016, other payable and accrued expenses consisted of the following:


	September 30, 2017		December 31, 2016
Lease expenses and payable for leasehold improvement due to a related party (note 12)	$	2,024	$	1,883
Commissions		688		757
Accrued warranty		529		290
Accrued payroll		2		398
Accrued professional fees		908		46
Accrued machine testing fee		405		—
Others		708		589

Total	$	5,264	$	3,963

Investors' Deposits	9 Months Ended
Investors' Deposits	Sep. 30, 2017
Banking and Thrift [Abstract]
Investors' Deposits	NOTE 8 – INVESTORS’ DEPOSITS On December 9, 2016, Shengxin (Shanghai) Management Consulting Limited Partnership (“SMC”), a related party (note 12), delivered RMB 20,124 (approximately $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 pursuant to which, in exchange for the SMC Investment, ACM issued to SMC a warrant exercisable to purchase 397,502 shares of ACM’s Class A common stock at a price of $7.50 per share (note 9).

Warrant Liability

9 Months Ended

Sep. 30, 2017

Text Block [Abstract]

Warrant Liability

NOTE 9 – WARRANT LIABILITY

On December 9, 2016, SMC delivered the SMC Investment to ACM Shanghai for potential investment pursuant to terms to be subsequently negotiated. As of December 31, 2016, the terms of the SMC Investment had not yet been negotiated and the SMC Investment was recorded as investors’ deposit.

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, ACM issued to SMC a 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 ACM’s Class A common stock at a price of $7.50 per share. Under the SMC Agreement, if SMC does not exercise the warrant by May 17, 2023, ACM Shanghai will be obligated, subject to approval of governmental authorities and ACM Shanghai’s equity holders, to deliver an equity interest of 3.6394% (subject to dilution) in satisfaction of the SMC Investment. If SMC exercises the warrant or if SMC does not exercise the warrant and the issuance of the equity interest in ACM Shanghai is not completed by August 17, 2023 due to the inability of the parties to obtain required governmental or equity holder approvals, then ACM Shanghai will be obligated to pay to SMC, in satisfaction of the SMC Investment, an amount equal to $2,981, converted into RMB at the lesser of 6.75 and the then-current RMB-to-US dollar exchange rate.

In accordance with FASB ASC 480, Distinguishing Liabilities from Equity, the warrant is classified as a liability as the warrant is conditional puttable. The fair value of the warrant is adjusted for changes in fair value at each reporting period but cannot be lower than the proceeds of the SMC Investment. The corresponding non-cash gain or loss of the changes in fair value is recorded in earnings. The methodology used to value the warrant was the Black-Scholes valuation model with the following assumptions:


	September 30, 2017
Fair value of common share (1)	$	7.23
Expected term in years (2)		5.63
Volatility (3)		28.73	%
Risk-free interest rate (4)		1.92	%
Expected dividend (5)		0	%

(1)	As the common stock was not publicly traded as of September 30. 2017, the Company used an independent third-party valuation firm to value the common stock price.

(2)	Expected term of the warrant represents the period from the current balance sheet date to the warrant expiration date.

(3)	Volatility is calculated based on the historical volatility of ACM’s comparable companies in the period equal to the expected term of the warrant.

(4)	Risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected term of the warrant.

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

Other Long-Term Liabilities

9 Months Ended

Sep. 30, 2017

Other Liabilities Disclosure [Abstract]

Other Long-Term Liabilities

NOTE 10 – OTHER LONG-TERM LIABILITIES

Other long-term liabilities represent government subsidies received from PRC governmental authorities for development and commercialization of certain technology but not yet recognized. As of September 30, 2017, and December 31, 2016, other long-term liabilities consisted of the following unearned government subsidies:


	September 30, 2017		December 31, 2016
Subsidies to Stress Free Polishing project, commenced in 2008	$	1,930	$	1,958
Subsidies to Electro Copper Plating project, commenced in 2014		4,710		4,921
Subsidies to Patent project, commenced in 2017		42		—

Total	$	6,682	$	6,879

Equity Method Investment	9 Months Ended
Equity Method Investment	Sep. 30, 2017
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investment	NOTE 11 – EQUITY METHOD 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. Undistributed earnings attributable to ACM’s equity method investment represented $20 of the consolidated retained earnings at September 30, 2017.

Related Party Balances and Transactions	9 Months Ended
Related Party Balances and Transactions	Sep. 30, 2017
Related Party Transactions [Abstract]
Related Party Balances and Transactions	NOTE 12 – RELATED PARTY BALANCES AND TRANSACTIONS On August 18, 2017, ACM and Ninebell, its equity method investment affiliate (note 11), entered into a loan agreement, pursuant to which ACM made an interest-free loan of $946 to Ninebell, payable in 180 days or automatically extended another 180 days if in default. The loan is secured by a pledge of Ninebell’s accounts receivable due from ACM and all money that Ninebell receives from ACM. ACM purchased materials from Ninebell amounting to $807 and $382 during the three months ended September 30, 2017 and 2016, respectively, and $2,624 and $1,446 during the nine months ended September 30, 2017 and 2016, respectively. As of September 30, 2017 and December 31, 2016, accounts payable due to Ninebell was $1,925 and $508, respectively. In 2007, ACM Shanghai entered into an operating lease agreement with Shanghai Zhangjiang Group Co., Ltd. (“Zhangjiang Group”), one of the holders of non-controlling interests in ACM Shanghai, to lease manufacturing and office space located in Shanghai, China. Pursuant to the lease agreement, Zhangjiang Group provided $771 to ACM Shanghai for leasehold improvements. In September 2016, the lease agreement was amended to modify payment terms and extend the lease through December 31, 2017. During the three and nine months ended September 30, 2017 and 2016, the Company incurred leasing expenses under the lease agreement of $130, $161, $451 and $491, respectively. As of September 30, 2017, and December 31, 2016, payables to Zhangjiang Group for lease expenses and leasehold improvements recorded as other payables and accrued expenses, amounted to $2,024 and $1,883, respectively (note 7). On December 9, 2016, ACM Shanghai received the SMC Investment from SMC for potential investment pursuant to terms to be subsequently negotiated (notes 8 and 9). SMC is a limited partnership incorporated in the PRC, whose partners consist of employees of ACM Shanghai. As of September 30, 2017, and December 31, 2016, investors’ deposits from SMC amounted to $0, and $2,902, respectively. 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, ACM issued to SMC a 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 ACM’s Class A common stock at a price of $7.50 per share, for a total exercise price of $2,981. Under the SMC Agreement, if SMC does not exercise the warrant by May 17, 2023, ACM Shanghai will be obligated, subject to approval of governmental authorities and ACM Shanghai’s equity holders, to deliver an equity interest of 3.6394% (subject to dilution) in satisfaction of the SMC Investment. If SMC exercises the warrant or if SMC does not exercise the warrant and the issuance of the equity interest in ACM Shanghai is not completed by August 17, 2023 due to the inability of the parties to obtain required governmental or equity holder approvals, then ACM Shanghai will be obligated to pay to SMC, in satisfaction of the SMC Investment, an amount equal to $2,981, converted into RMB at the lesser of 6.75 and the then-current RMB-to-US dollar exchange rate.

Leases

9 Months Ended

Sep. 30, 2017

Leases [Abstract]

Leases

NOTE 13 – LEASES

ACM entered into a two-year lease agreement in March 2015 for office and warehouse space of approximately 3,000 square feet for its headquarters in Fremont, California, at a rate of $2 per month. On March 22, 2017, ACM amended the lease agreement to extend the lease term through September 30, 2018 and increase the base rent to $3 per month.

ACM Shanghai entered into an operating lease agreement with Zhangjiang Group (a related party, see note 12) in 2007 for manufacturing and office space of approximately 63,510 square feet in Shanghai, China. The lease agreement has been amended several times to modify payment terms and extend the lease term, most recently through December 31, 2017. Monthly rent is $58 during 2017.

ACM Wuxi leases office space in Wuxi, China, at a rate of less than $1 per month.

Future minimum lease payments under the non-cancelable lease agreements as of September 30, 2017 and December 31, 2016 were as follows:


	September 30, 2017		December 31, 2016
2017	$	2,193	$	2,538
2018		9		8

Total	$	2,202	$	2,546

Rent expense was $140 and $168 for the three months ended September 30, 2017 and 2016, respectively, and $476 and $437 for the nine months ended September 30, 2017 and 2016, respectively.

Common Stock	9 Months Ended
Common Stock	Sep. 30, 2017
Equity [Abstract]
Common Stock	NOTE 14 – COMMON STOCK ACM is authorized to issue 100,000,000 shares of Class A common stock and 7,303,533 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 if 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 stock holders. In August 2017 ACM entered into a securities purchase agreement with Shanghai Pudong High-Tech Investment Co., Ltd. (“PDHTI”) and its subsidiary Pudong Science and Technology (Cayman) Co., Ltd. (“PST”), in which ACM agreed to bid, in an auction process mandated by PRC regulations, to purchase PDHTI’s 10.78% equity interests in ACM Shanghai and to sell shares of Class A common stock to PST. On September 8, 2017, ACM issued 1,119,576 shares of Class A common stock to PST for a purchase price of $7.50 per share, representing an aggregate purchase price of $8,397. The non-controlling equity interest transfer to ACM is subject to Chinese government’s approval and had not been closed as of September 30, 2017. In August 2017 ACM entered into a securities purchase agreement with Shanghai Zhangjiang Science & Technology Venture Capital Co., Ltd. (“ZSTVC”) and its subsidiary Zhangjiang AJ Company Limited (“ZJAJ”), in which ACM agreed to bid, in an auction process mandated by PRC regulations, to purchase ZSTVC’s 7.58% equity interests in ACM Shanghai and to sell shares of Class A common stock to ZJAJ. On September 8, 2017, ACM issued 787,098 shares of Class A common stock to ZJAJ for a purchase price of $7.50 per share, or an aggregate purchase price of $5,903. The non-controlling equity interest transfer to ACM is subject to Chinese government’s approval and had not been closed as of September 30, 2017. In September 2017 ACM issued 133,334 shares of Class A common stock to Ninebell for a purchase price of $7.50 per share, or an aggregate purchase price of $1,000 (note 11). At various dates during the nine months ended September 30, 2017, ACM issued 472,887 shares of Class A common stock for options exercised by certain employee and non-employees. At September 30, 2017 and December 31, 2016, the number of shares of Class A common stock issued and outstanding was 4,741,635 and 2,228,740, respectively. At September 30, 2017 and December 31, 2016, the number of shares of Class B common stock issued and outstanding was 2,409,738.

Redeemable Convertible Preferred Stock	9 Months Ended
Redeemable Convertible Preferred Stock	Sep. 30, 2017
Text Block [Abstract]
Redeemable Convertible Preferred Stock	NOTE 15 – REDEEMABLE CONVERTIBLE PREFERRED STOCK Upon ACM’s redomestication in Delaware in November 2016, ACM had 22,696,467 authorized shares of preferred stock, of which 385,000, 1,572,000, 1,360,962, 2,659,975, 10,718,530, and 6,000,000 shares were designated as Series A, Series B, Series C, Series D, Series E and Series F preferred stock, respectively. In March 2017 ACM entered into a securities purchase agreement, amended in July 2017, with Shanghai Science and Technology Venture Capital Co., Ltd. (“SSTVC”) pursuant to which, effective as of August 31, 2017, ACM acquired SSTVC’s equity interests in ACM Shanghai for a purchase price of $6,154 (RMB 40,000) and issued to SSTVC 4,998,508 shares of Series E convertible preferred stock for a purchase price of $5,800. The number of outstanding shares of Series A, Series B, Series C, Series D, Series E and Series F was 385,000, 1,572,000, 1,360,962, 1,326,642, 4,998,508 and 3,663,254, and 385,000, 1,572,000, 1,360,962, 1,326,642, 0 and 3,663,254, respectively, at September 30, 2017 and December 31, 2016. Shares of ACM’s convertible preferred stock have rights, preferences and privileges as follows: Voting Rights Each share of Series A through Series F convertible preferred stock is entitled to a number of votes equal to the number of whole shares of common stock into which such share can be converted. Dividends Holders of Series A through Series F convertible preferred stock have a non-cumulative right to participate in and receive the same dividends as may be declared for common stockholders, as and if declared by the Board of Directors, payable out of funds legally available. Conversion Each share of Series A through Series F convertible preferred stock is convertible at any time, at the option of the holder. At September 30, 2017, each share of Series A, B, E and F convertible preferred stock was convertible into one-third share of Class A common stock, each share of Series C convertible preferred stock was convertible into 0.3544 shares of Class A common stock, and each share of Series D convertible preferred stock was convertible into 0.4562 shares of Class A common stock. The Series A through Series F convertible preferred stock will convert automatically into Class A common stock upon the closing of an initial public offering of Class A common stock with aggregate proceeds of at least $20,000 and a per-share price of at least $15.00. At September 30, 2017 and December 31, 2016, 4,627,577 shares and 2,960,968 shares of Class A common stock were reserved for issuance upon conversion of outstanding Series A through Series F convertible preferred stock. *Liquidation Preferences* Holders of Series A through Series F convertible preferred stock are entitled to receive specified liquidation amounts in the event of a liquidation, dissolution or winding-up of ACM or of certain deemed liquidation events. The deemed liquidation events generally include (a) a merger or stock sale after which new stockholders would own a majority of the voting stock of ACM and (b) a sale of all or substantially all of the assets of the Company. In the event of a liquidation, dissolution or winding-up of ACM or a deemed liquidation, the holders of Series A through Series F convertible preferred stock shall be entitled to be paid, prior to and in preference to the holders of common stock, an amount equal to $0.80, $1.00, $1.50, $3.75, $1.00 and $2.50 per share of Series A through Series F convertible preferred stock, respectively, plus any accumulated and unpaid dividends as of the redemption date.

Stock-Based Compensation

9 Months Ended

Sep. 30, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation

NOTE 16 – STOCK-BASED COMPENSATION

ACM’s stock-based compensation awards consisting of employee and non-employee awards were issued under the 1998 Stock Option Plan and 2016 Omnibus Incentive Plan.

Employee Awards

The following table summarizes the Company’s employee share option activities during the nine months ended September 30, 2017:


	Number of Option Shares			Weighted Average Grant Date Fair Value		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
Outstanding at January 1, 2017		2,100,377		$	0.54	$	2.03		7.83
Granted		83,334			2.58		7.50
Exercised		(174,334	)		0.45		0.75
Expired		(903	)		0.55		3.00
Forfeited		(12,584	)		0.54		3.00
Outstanding at September 30, 2017		1,995,890		$	0.63	$	2.37		7.77
Vested and exercisable at September 30, 2017		902,821

ACM recognized employee stock-based compensation expense of $72 and $22 during the three months ended September 30, 2017 and 2016, respectively, and $200 and $68 during the nine months ended September 30, 2017 and 2016, respectively. As of September 30, 2017, and December 31, 2016, $712 and $726, 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 1.92 years and 2.25 years, respectively. Total recognized compensation cost may be adjusted for future changes in estimated forfeitures.

The fair value of each option granted to an employee during the nine months ended September 30, 2017 was estimated on the grant date using the Black-Scholes valuation model with the following assumptions. No options were granted to employees during the nine months ended September 30, 2016.


	September 30, 2017
Fair value of common share (1)	$	7.59
Expected term in years (2)		6.25
Volatility (3)		29.18	%
Risk-free interest rate (4)		2.22	%
Expected dividend (5)		0	%

(1)	As the common stock was not publicly traded, the Company used an independent third-party valuation firm to value the common stock.

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

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

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

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

Non-employee Awards

The following table summarizes the Company’s non-employee share option activities during the nine months ended September 30, 2017:


	Number of Option Shares			Weighted Average Grant Date Fair Value		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
Outstanding at January 1, 2017		1,578,565		$	0.51	$	1.58		6.81
Granted		133,335			2.46		7.50
Exercised		(298,555	)		0.39		0.93
Expired		(133,336	)		0.45		0.75
Outstanding at September 30, 2017		1,280,009		$	0.75	$	2.43		7.70
Vested and exercisable at September 30, 2017		686,875

The Company recognized non-employee stock-based compensation expense of $272 and $(23) during the three months ended September 30, 2017 and 2016, respectively, and $1,492 and $125 during the nine months ended September 30, 2017 and 2016, respectively.

The fair value of each option granted to a non-employee during the nine months ended September 30, 2017 was calculated by application of the Black-Scholes valuation model with the following assumptions. No options were granted to any non-employee during the nine months ended September 30, 2016.


	September 30, 2017
Fair value of common share (1)	$	6.87-7.59
Expected term in years (2)		6.25
Volatility (3)		29.18%-29.51%
Risk-free interest rate (4)		2.22%-2.43%
Expected dividend (5)		0%

(1)	As the common stock was not publicly traded, the Company used an independent third-party valuation firm to value the common stock.

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

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

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

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

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 17 – 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. Based on all available evidence, in particular the Company’s three-year historical cumulative losses, recent operating losses and U.S. pre-tax loss for the nine months ended September 30, 2017, the Company recorded a valuation allowance against its U.S. net deferred tax assets. In order to fully realize the U.S. deferred tax assets, the Company will need to generate sufficient taxable income in future periods before the expiration of the deferred tax assets governed by the tax code. In each period since inception, the Company has recorded a valuation allowance for the full amount of net deferred tax assets in the US, as the realization of deferred tax assets is uncertain. The China subsidiary 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 nine months ended September 30, 2017 and 2016. 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 34% for U.S. federal income tax purposes and 15%-25% for Chinese income tax purpose due to the effects of the valuation allowance and certain permanent differences as it pertains to book-tax differences. As a result, the company recorded a tax provision of $471 and $59 for the nine months ended September 30, 2017 and 2016. As of September 30, 2017, the Company’s total unrecognized tax benefits were approximately $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 nine months ended September 30, 2017. 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, 2016. To the extent the Company has tax attribute carryforwards, the tax years in which the attribute was generated may be adjusted upon examination by the U.S. Internal Revenue Service, state or foreign tax authorities to the extent utilized in a future period. As of September 30, 2017 and December 31, 2016, the Company intended that its PRC earnings would be indefinitely reinvested outside of the United States. Thus, deferred taxes were not, for U.S. federal income tax purposes, provided with respect to unremitted earnings from the PRC.

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 18 – COMMITMENTS AND CONTINGENCIES The Company leases offices under non-cancelable operating lease agreements. The rental expenses were $473 and $511 for the nine months ended September 30, 2017 and 2016, respectively. See note 13 for future minimum lease payments under non-cancelable operating lease agreements with initial terms of one year or more. The Company did not have any capital commitments during the reported periods. 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.

Subsequent Events

9 Months Ended

Sep. 30, 2017

Subsequent Events [Abstract]

Subsequent Events

NOTE 19 – SUBSEQUENT EVENTS

Under PRC regulations, PDHTI and ZSTVC could sell their minority ACM Shanghai equity interests (see note 14) only by means of auction processes. In October 2017 ACM was advised that its bids had won both auctions and that the sales of both of the minority equity interests would be completed by no later than December 31, 2017. Upon completion of the two auction processes, ACM will own all of the outstanding equity interests of ACM Shanghai.

In November 2017 ACM issued and sold 2,233,000 shares of Class A common stock in the IPO. Of the shares sold in the IPO, 2,000,000 were sold upon completion of the IPO on November 7, 2017 and 233,000 shares were sold on November 14, 2017 upon exercise of an over-allotment option granted to the underwriters of the IPO. In addition, on November 7, 2017, following the completion of the IPO, ACM issued and sold 1,333,334 shares of Class A common stock in a private placement to two entities (the “Private Placement”). All of the 3,566,334 shares of Class A common stock issued in the IPO and the Private Placement were sold at a price of $5.60 per share, for aggregate gross proceeds of $20.0 million. The Company received approximately $16.5 million in net proceeds after deducting underwriting discounts and commissions, placement fees, and offering costs.

•

Upon the closing of the IPO on November 7, 2017, all of the outstanding shares of convertible preferred stock automatically converted into 4,627,577 shares of Class A common stock at the respective conversion rates then in effect. Following the closing of the IPO, there were no shares of preferred stock outstanding.

•

In connection with the IPO, ACM amended and restated its certificate of incorporation to change the authorized capital stock to 50,000,000 shares of Class A common stock, 2,409,738 shares of Class B common stock, and 10,000,000 shares designated as preferred stock, all with a par value of $0.0001 per share.

The condensed consolidated financial statements as of September 30, 2017, including share and per share amounts, do not give effect to the IPO, the Private Placement, the conversion of the convertible preferred stock or the amendment and restatement of the certificate of incorporation as all of such events were completed subsequent to September 30, 2017.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2017

Accounting Policies [Abstract]

Basis of Presentation and Principles of Consolidation

Unaudited Pro Forma Balance Sheet

Use of Estimates

Restricted Cash

Deferred Initial Public Offering ("IPO") Costs

Deferred Initial Public Offering (“IPO”) Costs

Basic and Diluted Net Income (Loss) per Common Share

Basic and diluted net income (loss) per common share is calculated as follows:


	Three Months Ended September 30,					Nine Months Ended September 30,
	2017			2016		2017			2016
Numerator:
Net income (loss)	$	(1,282	)	$	561	$	(4,237	)	$	(468	)
Net income (loss) attributable to non-controlling interest		(327	)		199		(535	)		(277	)
Net income allocated to participating securities		—			205		—			—

Net income (loss) available to common stockholders, basic and diluted	$	(955	)	$	157	$	(3,702	)	$	(191	)

Denominator:
Weighted average shares outstanding, basic		5,581,637			2,108,324		5,148,255			2,077,115
Effect of dilutive securities		—			1,264,181		—			—

Weighted average shares outstanding, diluted		5,581,637			3,372,505		5,148,255			2,077,115

Net income (loss) per common share:
Basic	$	(0.17	)	$	0.07	$	(0.72	)	$	(0.09	)
Diluted	$	(0.17	)	$	0.05	$	(0.72	)	$	(0.09	)

Fair Value of Financial Instruments


Level 1:		Valuations for assets and liabilities traded in active exchange markets. Valuations are obtained from readily available pricing sources for market transactions involving identical assets or liabilities.

Level 2:		Valuations for assets and liabilities traded in less active dealer or broker markets. Valuations are obtained from third party pricing services for identical or similar assets or liabilities.

Level 3:		Valuations for assets and liabilities that are derived from other valuation methodologies, including option pricing models, discounted cash flow models and similar techniques, and not based on market exchange, dealer or broker traded transactions. Level 3 valuations incorporate certain unobservable assumptions and projections in determining the fair value assigned to such assets.

Fair Value Measured or Disclosed on a Recurring Basis


	Fair Value Measurement at Reporting Date Using
	Quoted Prices in Active Markets for Identical Liabilities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
As of September 30:
Liabilities:
Short-term borrowings	$	—	$	3,472	$	—	$	3,472
Warrant liability		—		—		3,033		3,033

		—		3,472		3,033		6,505

As of December 31, 2016:
Liabilities:
Short-term borrowings	$	—	$	4,761	$	—	$	4,761

Fair Value Measured on a Non-Recurring Basis

Recent Accounting Pronouncements

Accounting Pronouncements Recently Adopted in the Consolidated Financial Statements for the Nine Months Ended September 30, 2017

Recent Accounting Pronouncements Not Yet Adopted

Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2017

Accounting Policies [Abstract]

Calculation of Basic and Diluted Net Income (Loss) per Common Share

Basic and diluted net income (loss) per common share is calculated as follows:


	Three Months Ended September 30,					Nine Months Ended September 30,
	2017			2016		2017			2016
Numerator:
Net income (loss)	$	(1,282	)	$	561	$	(4,237	)	$	(468	)
Net income (loss) attributable to non-controlling interest		(327	)		199		(535	)		(277	)
Net income allocated to participating securities		—			205		—			—

Net income (loss) available to common stockholders, basic and diluted	$	(955	)	$	157	$	(3,702	)	$	(191	)

Denominator:
Weighted average shares outstanding, basic		5,581,637			2,108,324		5,148,255			2,077,115
Effect of dilutive securities		—			1,264,181		—			—

Weighted average shares outstanding, diluted		5,581,637			3,372,505		5,148,255			2,077,115

Net income (loss) per common share:
Basic	$	(0.17	)	$	0.07	$	(0.72	)	$	(0.09	)
Diluted	$	(0.17	)	$	0.05	$	(0.72	)	$	(0.09	)

Information About Inputs Into Fair Value Measurement Of Company's Liabilities that Are Measured And Recorded At Fair Value On A Recurring Basis In Periods Subsequent To Their Initial Recognition


	Fair Value Measurement at Reporting Date Using
	Quoted Prices in Active Markets for Identical Liabilities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
As of September 30:
Liabilities:
Short-term borrowings	$	—	$	3,472	$	—	$	3,472
Warrant liability		—		—		3,033		3,033

		—		3,472		3,033		6,505

As of December 31, 2016:
Liabilities:
Short-term borrowings	$	—	$	4,761	$	—	$	4,761

Accounts Receivable (Tables)

9 Months Ended

Sep. 30, 2017

Receivables [Abstract]

Accounts Receivable

At September 30, 2017 and December 31, 2016, accounts receivable consisted of the following:


	September 30, 2017		December 31, 2016
Accounts receivable	$	15,784	$	16,026
Less: Allowance for doubtful accounts		—		—

Total	$	15,784	$	16,026

Inventory (Tables)

9 Months Ended

Sep. 30, 2017

Inventory Disclosure [Abstract]

Inventory

At September 30, 2017 and December 31, 2016, inventory consisted of the following:


	September 30, 2017		December 31, 2016
Raw materials	$	7,343	$	7,698
Work in process		3,425		1,260
Finished goods		7,309		2,708

Total inventory, gross		18,077		11,666
Inventory reserve		—		—

Total inventory, net	$	18,077	$	11,666

Property, Plant and Equipment, Net (Tables)

9 Months Ended

Sep. 30, 2017

Property, Plant and Equipment [Abstract]

Property, plant and equipment

At September 30, 2017 and December 31, 2016, property, plant and equipment consisted of the following:


	September 30, 2017			December 31 2016
Manufacturing equipment	$	9,515		$	8,566
Office equipment		458			410
Transportation equipment		200			191
Leasehold improvement		243			224

Total cost		10,416			9,391
Less: Total accumulated depreciation		(8,070	)		(7,562	)
Construction in progress		—			433

Total property, plant and equipment, net	$	2,346		$	2,262

Short-Term Borrowings (Tables)

9 Months Ended

Sep. 30, 2017

Debt Disclosure [Abstract]

Short-term borrowing

At September 30, 2017 and December 31, 2016, short-term borrowing consisted of the following:


	September 30, 2017		December 31, 2016
Borrowings from Bank of China, due on February 10, 2017 with annual interest rate of 4.8%, secured by certain of the Company’s intellectual property and fully repaid on February 13, 2017	$	—	$	1,222
Borrowings from Bank of Shanghai Pudong Branch, due on June 24, 2017 with an annual interest rate of 5.66%, guaranteed by the Company’s CEO and fully repaid on June 25, 2017		—		281
Line of credit up to $3,605 from Bank of Shanghai Pudong Branch, due on July 3, 2017 with an annual interest rate of 5.66%, guaranteed by the Company’s CEO and fully repaid on June 7, 2017		—		1,455
Line of credit up to $3,670 from Bank of Shanghai Pudong Branch, due on July 3, 2017 with an annual interest rate of 3.2%, guaranteed by the Company’s CEO and fully repaid on May 18, 2017		—		1,803
Line of credit up to $4,521 from Bank of China Pudong Branch, due on March 5, 2018 with annual interest rate of 5.69%, secured by certain of the Company’s intellectual property		2,185		—
Line of credit up to $3,767 from Bank of Shanghai Pudong Branch, due on September 22,2018 with an annual interest rate of 5.66%, guaranteed by the Company’s CEO		663		—
Line of credit up to $3,767 from Bank of Shanghai Pudong Branch, due on September 23,2018 with an annual interest rate of 5.66%, guaranteed by the Company’s CEO		624		—

Total	$	3,472	$	4,761

Other Payable and Accrued Expenses (Tables)

9 Months Ended

Sep. 30, 2017

Payables and Accruals [Abstract]

Other payable and accrued expenses

At September 30, 2017 and December 31, 2016, other payable and accrued expenses consisted of the following:


	September 30, 2017		December 31, 2016
Lease expenses and payable for leasehold improvement due to a related party (note 12)	$	2,024	$	1,883
Commissions		688		757
Accrued warranty		529		290
Accrued payroll		2		398
Accrued professional fees		908		46
Accrued machine testing fee		405		—
Others		708		589

Total	$	5,264	$	3,963

Warrant Liability (Tables)

9 Months Ended

Sep. 30, 2017

Text Block [Abstract]

Black-Scholes valuation model assumptions used to value warrant

The methodology used to value the warrant was the Black-Scholes valuation model with the following assumptions:


	September 30, 2017
Fair value of common share (1)	$	7.23
Expected term in years (2)		5.63
Volatility (3)		28.73	%
Risk-free interest rate (4)		1.92	%
Expected dividend (5)		0	%

(1)	As the common stock was not publicly traded as of September 30. 2017, the Company used an independent third-party valuation firm to value the common stock price.

(2)	Expected term of the warrant represents the period from the current balance sheet date to the warrant expiration date.

(3)	Volatility is calculated based on the historical volatility of ACM’s comparable companies in the period equal to the expected term of the warrant.

(4)	Risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected term of the warrant.

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

Other Long-Term Liabilities (Tables)

9 Months Ended

Sep. 30, 2017

Other Liabilities Disclosure [Abstract]

Other long-term liabilities

As of September 30, 2017, and December 31, 2016, other long-term liabilities consisted of the following unearned government subsidies:


	September 30, 2017		December 31, 2016
Subsidies to Stress Free Polishing project, commenced in 2008	$	1,930	$	1,958
Subsidies to Electro Copper Plating project, commenced in 2014		4,710		4,921
Subsidies to Patent project, commenced in 2017		42		—

Total	$	6,682	$	6,879

Leases (Tables)

9 Months Ended

Sep. 30, 2017

Leases [Abstract]

Summary of Future Minimum Lease Payments under Non-cancelable Lease Agreements

Future minimum lease payments under the non-cancelable lease agreements as of September 30, 2017 and December 31, 2016 were as follows:


	September 30, 2017		December 31, 2016
2017	$	2,193	$	2,538
2018		9		8

Total	$	2,202	$	2,546

Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2017

Employee Awards [Member]

Summary of Share Option Activities

The following table summarizes the Company’s employee share option activities during the nine months ended September 30, 2017:


	Number of Option Shares			Weighted Average Grant Date Fair Value		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
Outstanding at January 1, 2017		2,100,377		$	0.54	$	2.03		7.83
Granted		83,334			2.58		7.50
Exercised		(174,334	)		0.45		0.75
Expired		(903	)		0.55		3.00
Forfeited		(12,584	)		0.54		3.00
Outstanding at September 30, 2017		1,995,890		$	0.63	$	2.37		7.77
Vested and exercisable at September 30, 2017		902,821

Summary of Assumptions used to Determine Fair Value of Share Options Granted


	September 30, 2017
Fair value of common share (1)	$	7.59
Expected term in years (2)		6.25
Volatility (3)		29.18	%
Risk-free interest rate (4)		2.22	%
Expected dividend (5)		0	%

(1)	As the common stock was not publicly traded, the Company used an independent third-party valuation firm to value the common stock.

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

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

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

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

Non-employee Awards [Member]

Summary of Share Option Activities

The following table summarizes the Company’s non-employee share option activities during the nine months ended September 30, 2017:


	Number of Option Shares			Weighted Average Grant Date Fair Value		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
Outstanding at January 1, 2017		1,578,565		$	0.51	$	1.58		6.81
Granted		133,335			2.46		7.50
Exercised		(298,555	)		0.39		0.93
Expired		(133,336	)		0.45		0.75
Outstanding at September 30, 2017		1,280,009		$	0.75	$	2.43		7.70
Vested and exercisable at September 30, 2017		686,875

Summary of Assumptions used to Determine Fair Value of Share Options Granted


	September 30, 2017
Fair value of common share (1)	$	6.87-7.59
Expected term in years (2)		6.25
Volatility (3)		29.18%-29.51%
Risk-free interest rate (4)		2.22%-2.43%
Expected dividend (5)		0%

(1)	As the common stock was not publicly traded, the Company used an independent third-party valuation firm to value the common stock.

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

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

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

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

Description of Business - Additional Information (Detail)		1 Months Ended
	Sep. 13, 2017	Aug. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Class A Common Stock [Member]
Schedule Of Description Of Business [Line Items]
1-for-3 reverse stock split	3
Common Class B [Member]
Schedule Of Description Of Business [Line Items]
1-for-3 reverse stock split	3
ACM Shanghai [Member]
Schedule Of Description Of Business [Line Items]
Purchase of ACM Shanghai's equity interests		18.77%
Outstanding equity interest			81.64%	62.87%
ACM Wuxi [Member]
Schedule Of Description Of Business [Line Items]
Outstanding equity interest			81.64%	62.87%

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Restricted cash	$ 433	$ 0
Deferred IPO costs	$ 819	$ 41

Summary of Significant Accounting Policies - Calculation of Basic and Diluted Net Income (Loss) per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Net income (loss)	$ (1,282)	$ 561	$ (4,237)	$ (468)
Net income (loss) attributable to non-controlling interest	(327)	199	(535)	(277)
Net income allocated to participating securities		205
Net income (loss) available to common stockholders, basic and diluted	$ (955)	$ 157	$ (3,702)	$ (191)
Denominator:
Weighted average shares outstanding, basic	5,581,637	2,108,324	5,148,255	2,077,115
Effect of dilutive securities		1,264,181
Weighted average shares outstanding, diluted	5,581,637	3,372,505	5,148,255	2,077,115
Net income (loss) per common share:
Basic	$ (0.17)	$ 0.07	$ (0.72)	$ (0.09)
Diluted	$ (0.17)	$ 0.05	$ (0.72)	$ (0.09)

Summary of Significant Accounting Policies - Information About Inputs Into Fair Value Measurement Of Company's Liabilities that Are Measured And Recorded At Fair Value On A Recurring Basis In Periods Subsequent To Their Initial Recognition (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Liabilities:
Short-term borrowings	$ 3,472	$ 4,761
Warrant liability	3,033
Financial and Nonfinancial Liabilities, Fair Value Disclosure, Total	6,505
Significant Other Observable Inputs (Level 2) [Member]
Liabilities:
Short-term borrowings	3,472	$ 4,761
Financial and Nonfinancial Liabilities, Fair Value Disclosure, Total	3,472
Significant Unobservable Inputs (Level 3) [Member]
Liabilities:
Warrant liability	3,033
Financial and Nonfinancial Liabilities, Fair Value Disclosure, Total	$ 3,033

Accounts Receivable - Composition of Accounts Receivable (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Receivables [Abstract]
Accounts receivable	$ 15,784	$ 16,026
Less: Allowance for doubtful accounts	0	0
Total	$ 15,784	$ 16,026

Accounts Receivable - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Receivables [Abstract]
Allowance for doubtful accounts	$ 0	$ 0
Accounts receivable were pledged as collateral for borrowings	$ 0	$ 0

Inventory - Details of Inventory (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Raw materials	$ 7,343	$ 7,698
Work in process	3,425	1,260
Finished goods	7,309	2,708
Total inventory, gross	18,077	11,666
Inventory reserve	0	0
Total inventory, net	$ 18,077	$ 11,666

Inventory - Additional Information (Detail) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Inventory reserve	$ 0	$ 0
Inventory pledged as collateral for borrowings	$ 0	$ 0

Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Total cost	$ 10,416	$ 9,391
Less: Total accumulated depreciation	(8,070)	(7,562)
Construction in progress		433
Total property, plant and equipment, net	2,346	2,262
Manufacturing equipment [Member]
Property, Plant and Equipment [Line Items]
Total cost	9,515	8,566
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Total cost	458	410
Transportation Equipment [Member]
Property, Plant and Equipment [Line Items]
Total cost	200	191
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total cost	$ 243	$ 224

Property, Plant and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Property Plant And Equipment Capitalized Interest Costs [Abstract]
Depreciation expense	$ 55	$ 31	$ 162	$ 119

Short-Term Borrowing (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Short-term Debt [Line Items]
Short-term borrowings	$ 3,472	$ 4,761
Borrowings from Bank of China, due on February 10, 2017 with annual interest rate of 4.8%, secured by certain of the Company's intellectual property and fully repaid on February 13, 2017 [Member]
Short-term Debt [Line Items]
Short-term borrowings		1,222
Borrowings from Bank of Shanghai Pudong Branch, due on June 24, 2017 with an annual interest rate of 5.66%, guaranteed by the Company's CEO and fully repaid on June 25, 2017 [Member]
Short-term Debt [Line Items]
Short-term borrowings		281
Line of credit up to $3,605 from Bank of Shanghai Pudong Branch, due on July 3, 2017 with an annual interest rate of 5.66%, guaranteed by the Company's CEO and fully repaid on May 18, 2017 [Member]
Short-term Debt [Line Items]
Short-term borrowings		1,455
Line of credit up to $3,670 from Bank of Shanghai Pudong Branch, due on July 3, 2017 with an annual interest rate of 3.2%, guaranteed by the Company's CEO and fully repaid on June 7, 2017 [Member]
Short-term Debt [Line Items]
Short-term borrowings		$ 1,803
Line of credit up to $4,521 from Bank of China Pudong Branch, due on March 5, 2018 with annual interest rate of 5.69%, secured by certain of the Company's intellectual property [Member]
Short-term Debt [Line Items]
Short-term borrowings	2,185
Line of credit up to $3,767 from Bank of Shanghai Pudong Branch, due on September 22,2018 with an annual interest rate of 5.66%, guaranteed by the Company's CEO [Member]
Short-term Debt [Line Items]
Short-term borrowings	663
Line of credit up to $3,767 from Bank of Shanghai Pudong Branch, due on September 23,2018 with an annual interest rate of 5.66%, guaranteed by the Company's CEO [Member]
Short-term Debt [Line Items]
Short-term borrowings	$ 624

Short-Term Borrowing (Parenthetical) (Detail) - USD ($)	9 Months Ended	12 Months Ended
Short-Term Borrowing (Parenthetical) (Detail) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Borrowings from Bank of China, due on February 10, 2017 with annual interest rate of 4.8%, secured by certain of the Company's intellectual property and fully repaid on February 13, 2017 [Member]
Short-term Debt [Line Items]
Maturity date		Feb. 10, 2017
Interest rate		4.80%
Repayment date		Feb. 13, 2017
Borrowings from Bank of Shanghai Pudong Branch, due on June 24, 2017 with an annual interest rate of 5.66%, guaranteed by the Company's CEO and fully repaid on June 25, 2017 [Member]
Short-term Debt [Line Items]
Maturity date		Jun. 24, 2017
Interest rate		5.66%
Repayment date		Jun. 25, 2017
Line of credit up to $3,605 from Bank of Shanghai Pudong Branch, due on July 3, 2017 with an annual interest rate of 5.66%, guaranteed by the Company's CEO and fully repaid on May 18, 2017 [Member]
Short-term Debt [Line Items]
Line of credit maximum borrowing capacity		$ 3,605,000
Maturity date		Jul. 03, 2017
Interest rate		5.66%
Repayment date		Jun. 07, 2017
Line of credit up to $3,670 from Bank of Shanghai Pudong Branch, due on July 3, 2017 with an annual interest rate of 3.2%, guaranteed by the Company's CEO and fully repaid on June 7, 2017 [Member]
Short-term Debt [Line Items]
Line of credit maximum borrowing capacity		$ 3,670,000
Maturity date		Jul. 03, 2017
Interest rate		3.20%
Repayment date		May 18, 2017
Line of credit up to $4,521 from Bank of China Pudong Branch, due on March 5, 2018 with annual interest rate of 5.69%, secured by certain of the Company's intellectual property [Member]
Short-term Debt [Line Items]
Line of credit maximum borrowing capacity	$ 4,521,000
Maturity date	Mar. 05, 2018
Interest rate	5.69%
Line of credit up to $3,767 from Bank of Shanghai Pudong Branch, due on September 22,2018 with an annual interest rate of 5.66%, guaranteed by the Company's CEO [Member]
Short-term Debt [Line Items]
Line of credit maximum borrowing capacity	$ 3,767,000
Maturity date	Sep. 22, 2018
Interest rate	5.66%
Line of credit up to $3,767 from Bank of Shanghai Pudong Branch, due on September 23,2018 with an annual interest rate of 5.66%, guaranteed by the Company's CEO [Member]
Short-term Debt [Line Items]
Line of credit maximum borrowing capacity	$ 3,767,000
Maturity date	Sep. 23, 2018
Interest rate	5.66%

Other Payable and Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Lease expenses and payable for leasehold improvement due to a related party (note 12)	$ 2,024	$ 1,883
Commissions	688	757
Accrued warranty	529	290
Accrued payroll	2	398
Accrued professional fees	908	46
Accrued machine testing fee	405
Others	708	589
Total	$ 5,264	$ 3,963

Investors' Deposits - Additional Information (Detail) $ / shares in Units, ¥ in Thousands, $ in Thousands	Mar. 14, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($)	Dec. 09, 2016 CNY (¥)	Dec. 09, 2016 USD ($)
Deposit Liabilities [Line Items]
Investors' deposit \| $		$ 2,902
Shengxin (Shanghai) Management Consulting Limited Partnership [Member]
Deposit Liabilities [Line Items]
Investors' deposit	$ 2,981		¥ 20,124	$ 2,981
Warrant exercisable to purchase shares of Class A common stock \| shares	397,502
warrant exercisable to purchase common stock price \| $ / shares	$ 7.50

Warrant Liability - Additional Information (Detail) $ / shares in Units, ¥ in Thousands, $ in Thousands	Mar. 14, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($)	Dec. 09, 2016 CNY (¥)	Dec. 09, 2016 USD ($)
Class of Warrant or Right [Line Items]
Investors' deposit \| $		$ 2,902
Shengxin (Shanghai) Management Consulting Limited Partnership [Member]
Class of Warrant or Right [Line Items]
Warrant exercisable to purchase shares of Class A common stock \| shares	397,502
warrant exercisable to purchase common stock price \| $ / shares	$ 7.50
Warrant exercisable date	May 17, 2023
Equity interest percentage in satisfaction of SMC Investment if warrant not exercise	3.6394%
Investors' deposit	$ 2,981		¥ 20,124	$ 2,981
RMB-to-US dollar exchange rate	6.75

Black-Scholes Valuation Model Assumptions Used to Value Warrant (Detail) - Warrant [Member]

9 Months Ended

Sep. 30, 2017

$ / shares

Class of Warrant or Right [Line Items]

Fair value of common share

$ 7.23

^[1]

Expected term in years

5 years 7 months 17 days

^[2]

Volatility

28.73%

^[3]

Risk-free interest rate

1.92%

^[4]

Expected dividend

0.00%

^[5]

[1]	As the common stock was not publicly traded as of September 30. 2017, the Company used an independent third-party valuation firm to value the common stock price.
[2]	Expected term of the warrant represents the period from the current balance sheet date to the warrant expiration date.
[3]	Volatility is calculated based on the historical volatility of ACM's comparable companies in the period equal to the expected term of the warrant.
[4]	Risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected term of the warrant.
[5]	Expected dividend is assumed to be 0% as ACM has no history or expectation of paying a dividend on its common stock.

Black-Scholes Valuation Model Assumptions Used to Value Warrant (Parenthetical) (Detail)

9 Months Ended

Sep. 30, 2017

Warrant [Member]

Class of Warrant or Right [Line Items]

Expected dividend

0.00%

^[1]

[1]	Expected dividend is assumed to be 0% as ACM has no history or expectation of paying a dividend on its common stock.

Other Long-Term Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Other Long Term Liabilities [Line Items]
Other long-term liabilities	$ 6,682	$ 6,879
Subsidies to Stress Free Polishing project [Member]
Other Long Term Liabilities [Line Items]
Other long-term liabilities	1,930	1,958
Subsidies to Electro Copper Plating project [Member]
Other Long Term Liabilities [Line Items]
Other long-term liabilities	4,710	$ 4,921
Subsidies to Patent project [Member]
Other Long Term Liabilities [Line Items]
Other long-term liabilities	$ 42

Equity Method Investment - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended
	Sep. 11, 2017	Sep. 30, 2017
Post-closing equity purchase price		$ 1,200
Ninebell [Member]
Equity method investment percentage	20.00%
Post-closing equity purchase price	$ 1,200
Purchase price of equity method investment, shares issued	133,334
Purchase price of equity method investment	$ 1,000
Purchase price of equity method investment, per share	$ 7.50
Undistributed earnings attributable to ACM's equity method investment		$ 20

Related Party Balances and Transactions - Additional Information (Detail) $ / shares in Units, ¥ in Thousands			3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 18, 2017 USD ($)	Mar. 14, 2017 USD ($) $ / shares	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 09, 2016 CNY (¥)	Dec. 09, 2016 USD ($)	Dec. 31, 2007 USD ($)
Related Party Transaction [Line Items]
Accounts payable-related party			$ 1,925,000		$ 1,925,000		$ 508,000
Investors' deposit							2,902,000
Ninebell [Member] \| Loan Agreement [Member]
Related Party Transaction [Line Items]
Interest-free loans	$ 946,000
Loan payable period	180 days
Purchased materials amount			807,000	$ 382,000	2,624,000	$ 1,446,000
Accounts payable-related party			1,925,000		1,925,000		508,000
Shanghai Zhangjiang Group Co., Ltd. [Member] \| Operating Lease Agreement [Member]
Related Party Transaction [Line Items]
Leasehold improvements										$ 771,000
Leasing expense under lease agreement			130,000	$ 451,000	161,000	$ 491,000
Lease expenses and payable for leasehold improvement due to a related party					2,024,000		1,883,000
Shengxin (Shanghai) Management Consulting Limited Partnership [Member]
Related Party Transaction [Line Items]
Investors' deposit		$ 2,981,000						¥ 20,124	$ 2,981,000
Stock issued, price per share \| $ / shares		$ 7.50
Exchange rate		6.75
Shengxin (Shanghai) Management Consulting Limited Partnership [Member] \| Class A Common Stock [Member]
Related Party Transaction [Line Items]
Stock issued, shares		$ 397,502
Stock issued, price per share \| $ / shares		$ 7.50
Total exercise price		$ 2,981,000
Shengxin (Shanghai) Management Consulting Limited Partnership [Member] \| ACM Shanghai [Member]
Related Party Transaction [Line Items]
Investors' deposit			$ 0		$ 0		$ 2,902,000
Equity interest percentage			3.6394%		3.6394%
Warrant obligation due to the inability of the parties to obtain required governmental or equity holder approvals					$ 2,981,000
Exchange rate			6.75		6.75

Leases - Additional Information (Detail) $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended
Leases - Additional Information (Detail) $ in Thousands	Mar. 22, 2017 $ / ft²	Mar. 31, 2015 ft² $ / ft²	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) $ / ft²	Sep. 30, 2016 USD ($)	Dec. 31, 2007 ft²
Property Subject to or Available for Operating Lease [Line Items]
Rent expense					$ 473	$ 511
Rent expense			$ 140	$ 168	$ 476	$ 437
California [Member] \| Lease Agreements [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease agreement period		2 years
Area of property under lease agreement \| ft²		3,000
Rate per square feet \| $ / ft²	3	2
Lease agreement extended date					Extend the lease term through September 30, 2018
China [Member] \| ACM Wuxi [Member]
Property Subject to or Available for Operating Lease [Line Items]
Rate per square feet \| $ / ft²					1
China [Member] \| Operating Lease [Member] \| Shanghai Zhangjiang Group Co., Ltd. [Member] \| ACM Shanghai [Member]
Property Subject to or Available for Operating Lease [Line Items]
Area of property under lease agreement \| ft²							63,510
Rent expense					$ 58

Leases - Future Minimum Lease Payments under Non-cancelable Lease Agreements (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Operating Leases, Future Minimum Payments Receivable [Abstract]
2017	$ 2,193	$ 2,538
2018	9	8
Total	$ 2,202	$ 2,546

Common Stock - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended
	Sep. 08, 2017	Sep. 30, 2017	Aug. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Stock conversion basis		Class B common stock is entitled to twenty votes and is convertible at any time into one share of Class A common stock
Shanghai Pudong High-Tech Investment Co., Ltd. [Member]
Class of Stock [Line Items]
Percentage of equity interest			10.78%
Zhangjiang Science and Technology Venture Capital Co Ltd [Member]
Class of Stock [Line Items]
Percentage of equity interest			7.58%
Class A Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares authorized		100,000,000		100,000,000
Common stock, par value		$ 0.0001		$ 0.0001
Common stock, shares issued		4,741,635		2,228,740
Common stock, shares outstanding		4,741,635		2,228,740
Class A Common Stock [Member] \| Employee and Non-employee [Member]
Class of Stock [Line Items]
Common stock, shares issued		472,887
Class A Common Stock [Member] \| Ninebell [Member]
Class of Stock [Line Items]
Common stock, shares issued		133,334
Common stock issued price per share		$ 7.50
Aggregate stock purchase price		$ 1,000
Class A Common Stock [Member] \| Pudong Science and Technology (Cayman) Co., Ltd. [Member]
Class of Stock [Line Items]
Common stock, shares issued	1,119,576
Common stock issued price per share	$ 7.50
Aggregate stock purchase price	$ 8,397
Class A Common Stock [Member] \| Zhangjiang AJ Company Limited [Member]
Class of Stock [Line Items]
Common stock, shares issued	787,098
Common stock issued price per share	$ 7.50
Aggregate stock purchase price	$ 5,903
Common Class B [Member]
Class of Stock [Line Items]
Common stock, shares authorized		7,303,533		7,303,533
Common stock, par value		$ 0.0001		$ 0.0001
Common stock, shares issued		2,409,738		2,409,738
Common stock, shares outstanding		2,409,738		2,409,738

Redeemable Convertible Preferred Stock - Additional Information (Detail) $ / shares in Units, ¥ in Thousands, $ in Thousands	1 Months Ended		9 Months Ended
	Mar. 31, 2017 CNY (¥)	Mar. 31, 2017 USD ($) shares	Sep. 30, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) shares
Temporary Equity [Line Items]
Redeemable preferred stock, shares authorized			22,696,467
Purchase of non-controlling interest \| $			$ 6,154
Series E convertible preferred stock purchase price \| $			$ 23,834	$ 18,034
Conversion of outstanding preferred stock, reserved for issuance			4,627,577	2,960,968
Shanghai Science and Technology Venture Capital Co Ltd [Member]
Temporary Equity [Line Items]
Purchase of non-controlling interest	¥ 40,000	$ 6,154
Series A Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Redeemable preferred stock, shares authorized			385,000	385,000
Redeemable preferred stock, shares issued			385,000	385,000
Series E convertible preferred stock purchase price \| $			$ 288	$ 288
Redeemable preferred stock, shares outstanding			385,000	385,000
Convertible preferred stock convertible into common stock			0.3333
Convertible preferred stock price per share \| $ / shares			$ 0.80
Series B Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Redeemable preferred stock, shares authorized			1,572,000	1,572,000
Redeemable preferred stock, shares issued			1,572,000	1,572,000
Series E convertible preferred stock purchase price \| $			$ 1,572	$ 1,572
Redeemable preferred stock, shares outstanding			1,572,000	1,572,000
Convertible preferred stock convertible into common stock			0.3333
Convertible preferred stock price per share \| $ / shares			$ 1.00
Series C Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Redeemable preferred stock, shares authorized			1,360,962	1,360,962
Redeemable preferred stock, shares issued			1,360,962	1,360,962
Series E convertible preferred stock purchase price \| $			$ 2,041	$ 2,041
Redeemable preferred stock, shares outstanding			1,360,962	1,360,962
Convertible preferred stock convertible into common stock			0.3544
Convertible preferred stock price per share \| $ / shares			$ 1.50
Series D Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Redeemable preferred stock, shares authorized			2,659,975	2,659,975
Redeemable preferred stock, shares issued			1,326,642	1,326,642
Series E convertible preferred stock purchase price \| $			$ 4,975	$ 4,975
Redeemable preferred stock, shares outstanding			1,326,642	1,326,642
Convertible preferred stock convertible into common stock			0.4562
Convertible preferred stock price per share \| $ / shares			$ 3.75
Series E Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Redeemable preferred stock, shares authorized			10,718,530	10,718,530
Redeemable preferred stock, shares issued			4,998,508	0
Series E convertible preferred stock purchase price \| $			$ 5,800
Redeemable preferred stock, shares outstanding			4,998,508	0
Convertible preferred stock convertible into common stock			0.3333
Convertible preferred stock price per share \| $ / shares			$ 1.00
Series E Convertible Preferred Stock [Member] \| Shanghai Science and Technology Venture Capital Co Ltd [Member]
Temporary Equity [Line Items]
Redeemable preferred stock, shares issued		4,998,508
Series E convertible preferred stock purchase price \| $		$ 5,800
Series F Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Redeemable preferred stock, shares authorized			6,000,000	6,000,000
Redeemable preferred stock, shares issued			3,663,254	3,663,254
Series E convertible preferred stock purchase price \| $			$ 9,158	$ 9,158
Redeemable preferred stock, shares outstanding			3,663,254	3,663,254
Convertible preferred stock convertible into common stock			0.3333
Convertible preferred stock price per share \| $ / shares			$ 2.50
Class A Common Stock [Member]
Temporary Equity [Line Items]
Aggregate proceeds from initial public offering of common stock \| $			$ 20,000
Common stock per share price \| $ / shares			$ 15.00

Stock-Based Compensation - Summary of Employee Share Option Activities (Detail) - Employee Awards [Member] - $ / shares	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Option Shares, Outstanding, Beginning balance	2,100,377
Number of Option Shares, Outstanding, Granted	83,334	0
Number of Option Shares, Outstanding, Exercised	(174,334)
Number of Option Shares, Outstanding, Expired	(903)
Number of Option Shares, Outstanding, Forfeited	(12,584)
Number of Option Shares, Outstanding, Ending balance	1,995,890		2,100,377
Vested and exercisable at September 30, 2017	902,821
Weighted Average Grant Date Fair Value, Outstanding, Beginning balance	$ 0.54
Weighted Average Grant Date Fair Value, Granted	2.58
Weighted Average Grant Date Fair Value, Exercised	0.45
Weighted Average Grant Date Fair Value, Expired	0.55
Weighted Average Grant Date Fair Value, Forfeited	0.54
Weighted Average Grant Date Fair Value, Outstanding, Ending balance	0.63		$ 0.54
Weighted Average Exercise Price, Outstanding, Beginning balance	2.03
Weighted Average Exercise Price, Granted	7.50
Weighted Average Exercise Price, Exercised	0.75
Weighted Average Exercise Price, Expired	3.00
Weighted Average Exercise Price, Forfeited	3.00
Weighted Average Exercise Price, Outstanding, Ending balance	$ 2.37		$ 2.03
Weighted Average Remaining Contractual Term, Outstanding	7 years 9 months 7 days		7 years 9 months 29 days

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Employee Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 72	$ 22	$ 200	$ 68
Unrecognized employee stock-based compensation expense, net of estimated forfeitures	712		$ 712		$ 726
weighted-average period over which unrecognized compensation is expected to be recognized			1 year 11 months 1 day		2 years 3 months
Number of options granted			83,334	0
Non-employee Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 272	$ (23)	$ 1,492	$ 125
Number of options granted			133,335	0

Stock-Based Compensation - Summary of Assumptions used to Determine Fair Value of Employee Share Options Granted (Detail) - Employee Awards [Member]

9 Months Ended

Sep. 30, 2017

$ / shares

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Fair value of common share

$ 7.59

^[1]

Expected term in years

6 years 3 months

^[2]

Volatility

29.18%

^[3]

Risk-free interest rate

2.22%

^[4]

Expected dividend

0.00%

^[5]

[1]	As the common stock was not publicly traded, the Company used an independent third-party valuation firm to value the common stock.
[2]	Expected term of share options is based on the average of the vesting period and the contractual term for each grant according to Staff Accounting Bulletin 110.
[3]	Volatility is calculated based on the historical volatility of ACM's comparable companies in the period equal to the expected term of each grant.
[4]	Risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected term of the share options in effect at the time of grant.
[5]	Expected dividend is assumed to be 0% as ACM has no history or expectation of paying a dividend on its common stock.

Stock-Based Compensation - Summary of Assumptions used to Determine Fair Value of Employee Share Options Granted (Parenthetical) (Detail)

9 Months Ended

Sep. 30, 2017

Employee Awards [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Expected dividend

0.00%

^[1]

[1]	Expected dividend is assumed to be 0% as ACM has no history or expectation of paying a dividend on its common stock.

Stock-Based Compensation - Summary of Non-employee Share Option Activities (Detail) - Non-employee Awards [Member] - $ / shares	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Option Shares, Outstanding, Beginning balance	1,578,565
Number of Option Shares, Outstanding, Granted	133,335	0
Number of Option Shares, Outstanding, Exercised	(298,555)
Number of Option Shares, Outstanding, Expired	(133,336)
Number of Option Shares, Outstanding, Ending balance	1,280,009		1,578,565
Vested and exercisable at September 30, 2017	686,875
Weighted Average Grant Date Fair Value, Outstanding, Beginning balance	$ 0.51
Weighted Average Grant Date Fair Value, Granted	2.46
Weighted Average Grant Date Fair Value, Exercised	0.39
Weighted Average Grant Date Fair Value, Expired	0.45
Weighted Average Grant Date Fair Value, Outstanding, Ending balance	0.75		$ 0.51
Weighted Average Exercise Price, Outstanding, Beginning balance	1.58
Weighted Average Exercise Price, Granted	7.50
Weighted Average Exercise Price, Exercised	0.93
Weighted Average Exercise Price, Expired	0.75
Weighted Average Exercise Price, Outstanding, Ending balance	$ 2.43		$ 1.58
Weighted Average Remaining Contractual Term, Outstanding	7 years 8 months 12 days		6 years 9 months 22 days

Stock-Based Compensation - Summary of Assumptions used to Determine Fair Value of Non-employee Share Options Granted (Detail) - Non-employee Awards [Member]

9 Months Ended

Sep. 30, 2017

$ / shares

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Expected term in years

6 years 3 months

^[1]

Volatility, minimum

29.18%

^[2]

Volatility, maximum

29.51%

^[2]

Risk-free interest rate, minimum

2.22%

^[3]

Risk-free interest rate, maximum

2.43%

^[3]

Expected dividend

0.00%

^[4]

Minimum [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Fair value of common share

$ 6.87

^[5]

Maximum [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Fair value of common share

$ 7.59

^[5]

[1]	Expected term of share options is based on the average of the vesting period and the contractual term for each grant according to Staff Accounting Bulletin 110
[2]	Volatility is calculated based on the historical volatility of ACM's comparable companies in the period equal to the expected term of each grant.
[3]	Risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected term of the share options in effect at the time of grant.
[4]	Expected dividend is assumed to be 0% as ACM has no history or expectation of paying a dividend on its common stock.
[5]	As the common stock was not publicly traded, the Company used an independent third-party valuation firm to value the common stock.

Stock-Based Compensation - Summary of Assumptions used to Determine Fair Value of Non-employee Share Options Granted (Parenthetical) (Detail)

9 Months Ended

Sep. 30, 2017

Non-employee Awards [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Expected dividend

0.00%

^[1]

[1]	Expected dividend is assumed to be 0% as ACM has no history or expectation of paying a dividend on its common stock.

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Taxes [Line Items]
Statutory U.S federal income tax rate			34.00%
Income tax provision (benefit)	$ (278,000)	$ 132,000	$ 471,000	$ 59,000
Unrecognized tax benefits	$ 44,000		44,000
Interest or penalties related to unrecognized tax benefits			$ 0
Earliest Tax Year [Member]
Income Taxes [Line Items]
Open tax year			2009
Latest Tax Year [Member]
Income Taxes [Line Items]
Open tax year			2016
Minimum [Member]
Income Taxes [Line Items]
Statutory Chinese income tax rate			15.00%
Maximum [Member]
Income Taxes [Line Items]
Statutory Chinese income tax rate			25.00%

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Commitments And Contingencies [Line Items]
Rental expenses	$ 473	$ 511
Minimum [Member]
Commitments And Contingencies [Line Items]
Lease, term of contract	1 year

Subsequent Events - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions			1 Months Ended
	Nov. 14, 2017	Nov. 07, 2017	Nov. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Class A Common Stock [Member]
Subsequent Event [Line Items]
Common stock, shares authorized				100,000,000	100,000,000
Common stock, par value per share				$ 0.0001	$ 0.0001
Common Class B [Member]
Subsequent Event [Line Items]
Common stock, shares authorized				7,303,533	7,303,533
Common stock, par value per share				$ 0.0001	$ 0.0001
Subsequent Event [Member]
Subsequent Event [Line Items]
Preferred stock, shares authorized			10,000,000
Preferred stock, par value per share			$ 0.0001
Subsequent Event [Member] \| Class A Common Stock [Member]
Subsequent Event [Line Items]
Shares issued and sold	3,566,334
Stock price	$ 5.60
Aggregate gross proceeds	$ 20.0
Net proceeds after deducting underwriting discounts and commissions, placement fees, and offering costs	$ 16.5
Number of shares converted		4,627,577
Common stock, shares authorized			50,000,000
Common stock, par value per share			$ 0.0001
Subsequent Event [Member] \| Common Class B [Member]
Subsequent Event [Line Items]
Common stock, shares authorized			2,409,738
Common stock, par value per share			$ 0.0001
Subsequent Event [Member] \| IPO [Member] \| Class A Common Stock [Member]
Subsequent Event [Line Items]
Shares issued and sold		2,000,000	2,233,000
Subsequent Event [Member] \| Over-Allotment Option [Member] \| Class A Common Stock [Member]
Subsequent Event [Line Items]
Shares issued and sold	233,000
Subsequent Event [Member] \| Private Placement [Member] \| Class A Common Stock [Member]
Subsequent Event [Line Items]
Shares issued and sold			1,333,334