0001140361-20-017994 | 10-Q | XBRL Viewer

Components of Stock-based Compensation Expense

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
Stock-Based Compensation Expense:
Cost of revenue	$	43	$	29	$	88	$	59
Sales and marketing expense		164		46		258		80
Research and development expense		188		94		375		180
General and administrative expense		460		449		823		1,043
	$	855	$	618	$	1,544	$	1,362

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
Stock-based compensation expense by type:
Employee stock purchase plan	$	635	$	291	$	1,066	$	512
Non-employee stock purchase plan		140		327		312		850
Subsidiary option grants		80		-		166		-
	$	855	$	618	$	1,544	$	1,362

Assumptions Used to Determine Fair Value of Share Options Granted

	Six Months Ended June 30,
	2020
Fair value of common share(1)	$22.07-38.26
Expected term in years(2)	5.50-6.25
Volatility(3)	42.17%-46.14%
Risk-free interest rate(4)	0.51%-0.82%
Expected dividend(5)	0%

(1)	Common stock value was the close market value on the grant date.

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

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

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

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

The fair value of option granted to employee with market based condition is estimated on the grant date using the Monte Carlo simulation model with the following assumptions.

	Six Months Ended June 30,
	2020
Fair value of common share(1)	$22.07
Expected term in years(2)	9.20 - 9.80
Volatility(3)	45.10%
Risk-free interest rate(4)	2.68%
Expected dividend(5)	0%

(1)	Common stock value was the close market value on the grant date.

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

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

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

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

Employee Share Option [Member]

Summary of Share Option Activities

The following table summarizes the Company’s employee share option activities during the six months ended June 30, 2020:

	Number of Option Share			Weighted Average Grant Date Fair Value		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
Outstanding at December 31, 2019		2,994,063		$	2.59	$	6.77	7.05 years
Granted		708,399			9.88		24.13		-
Exercised		(41,172	)		2.71		6.47
Expired		-			-		-
Forfeited/cancelled		(39,120	)		5.10		13.46
Outstanding at June 30, 2020		3,622,170		$	3.98	$	10.10	7.16 years
Vested and exercisable at June 30, 2020		1,997,526

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

Summary of Share Option Activities

The following table summarizes the ACM Shanghai employee stock option activities during the six months ended June 30, 2020:

	Number of Option Shares in ACM Shanghai			Weighted Average Grant Date Fair Value		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
Outstanding at December 31, 2019		-		$	-	$	-		-
Granted		5,869,808			0.22		1.87
Exercised		-			-		-
Expired		-			-		-
Forfeited/cancelled		(330,770	)		0.23		1.87
Outstanding at June 30, 2020		5,539,038		$	0.22	$	1.87	4.01 years
Vested and exercisable at June 30, 2020		-

Non-Employee Stock Option [Member]

Summary of Share Option Activities

The following table summarizes ACM’s non-employee stock option activities during the six months ended June 30, 2020:

	Number of Option Shares			Weighted Average Grant Date Fair Value		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
Outstanding at December 31, 2019		1,101,613		$	0.82	$	2.69	5.85 years
Granted		20,000			10.29		25.60		-
Exercised		(144,731	)		1.22		4.19
Expired		-
Forfeited/cancelled		-
Outstanding at June 30, 2020		976,882		$	0.95	$	2.93	5.39 years
Vested and exercisable at June 30, 2020		929,397

INCOME TAXES (Tables)

6 Months Ended

Jun. 30, 2020

INCOME TAXES [Abstract]

Income Tax Expense

Income tax expense was as follows:

	Six Months Ended June 30,						Three Months Ended June 30,
	2020			2019			2020			2019
	(in thousands)						(in thousands)
Total income tax expense	$	(2,163	)	$	(995	)	$	(1,859	)	$	(876	)

DESCRIPTION OF BUSINESS (Details) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended	12 Months Ended
DESCRIPTION OF BUSINESS (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jun. 30, 2020	Dec. 31, 2019
ACM Research (Shanghai), Inc. [Member]
Description of Business [Abstract]
Purchase of equity interest percentage			8.30%
Name of subsidiaries		ACM Research (Shanghai), Inc.
Term to complete listing of shares	3 years
Date and place of Incorporation		China, May 2005
Effective interest held as at		91.70%	91.70%
ACM Research (Wuxi), Inc. [Member]
Description of Business [Abstract]
Name of subsidiaries		ACM Research (Wuxi), Inc.
Date and place of Incorporation		China, July 2011
Effective interest held as at		91.70%	91.70%
CleanChip Technologies Limited [Member]
Description of Business [Abstract]
Proceeds from sale of interest in subsidiary			$ 3,500
Name of subsidiaries		CleanChip Technologies Limited
Date and place of Incorporation		Hong Kong, June 2017
Effective interest held as at		91.70%	91.70%
ACM Research Korea CO., LTD [Member]
Description of Business [Abstract]
Name of subsidiaries		ACM Research Korea CO., LTD.
Date and place of Incorporation		Korea, December 2017
Effective interest held as at		91.70%	91.70%
Shengwei Research (Shanghai), Inc. [Member]
Description of Business [Abstract]
Purchase of equity interest percentage			91.70%
Name of subsidiaries		Shengwei Research (Shanghai), Inc.
Date and place of Incorporation		China, March 2019
Effective interest held as at		91.70%	91.70%
ACM Research (CA), Inc. [Member]
Description of Business [Abstract]
Name of subsidiaries		ACM Research (CA), Inc.
Date and place of Incorporation		USA, June 2019
Effective interest held as at		91.70%	91.70%
ACM Research (Cayman), Inc. [Member]
Description of Business [Abstract]
Name of subsidiaries		ACM Research (Cayman), Inc.
Date and place of Incorporation		Cayman Islands, April 2019
Effective interest held as at		100.00%	100.00%

SIGNIFICANT ACCOUNTING POLICIES, Basic and Diluted Net Income per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator [Abstract]
Net income	$ 496	$ 4,311	$ 2,459	$ 6,168
Net income attributable to non-controlling interests and redeemable non-controlling interests	577	0	835	0
Net income (loss) available to common stockholders, basic and diluted	$ (81)	$ 4,311	$ 1,624	$ 6,168
Weighted average shares outstanding, basic (in shares)	18,050,841	16,090,937	18,085,602	16,067,924
Effect of dilutive securities (in shares)	3,465,334	2,513,410	3,111,601	2,387,610
Weighted average shares outstanding, diluted (in shares)	21,516,175	18,604,347	21,197,203	18,455,534
Net income (loss) per common share:
Basic (in dollars per share)	$ 0.00	$ 0.27	$ 0.09	$ 0.38
Diluted (in dollars per share)	$ 0.00	$ 0.23	$ 0.08	$ 0.33

SIGNIFICANT ACCOUNTING POLICIES, Concentration of Credit Risk (Details) - Customer	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accounts Receivable [Member]
Concentration of Credit Risk [Abstract]
Number of major customers	3	3	3	3
Concentration of credit risk	91.00%	89.90%	92.40%	72.10%
Revenue Benchmark [Member]
Concentration of Credit Risk [Abstract]
Number of major customers	3	3
Concentration of credit risk	83.90%	67.70%

ACCOUNTS RECEIVABLE (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accounts Receivable [Abstract]
Accounts receivable	$ 58,903	$ 31,091
Less: allowance for doubtful accounts	0	0
Total	58,903	31,091
Accounts receivable pledged as collateral for borrowings	$ 0	$ 1,433

INVENTORIES (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Inventory [Abstract]
Raw materials	$ 18,569	$ 15,105
Work in process	14,203	10,407
Finished goods	17,000	19,284
Total inventory	$ 49,772	$ 44,796

PROPERTY, PLANT AND EQUIPMENT, NET (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Total cost	$ 6,297		$ 6,297		$ 6,095
Less: Total accumulated depreciation	(3,447)		(3,447)		(3,077)
Construction in progress	1,106		1,106		601
Total property, plant and equipment, net	3,956		3,956		3,619
Depreciation expense	189	$ 177	374	$ 352
Manufacturing Equipment [Member]
Property, Plant and Equipment [Abstract]
Total cost	3,936		3,936		3,902
Office Equipment [Member]
Property, Plant and Equipment [Abstract]
Total cost	762		762		627
Transportation Equipment [Member]
Property, Plant and Equipment [Abstract]
Total cost	171		171		124
Leasehold Improvement [Member]
Property, Plant and Equipment [Abstract]
Total cost	$ 1,428		$ 1,428		$ 1,442

SHORT-TERM BORROWINGS (Details) ¥ in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 CNY (¥)	Dec. 31, 2019 USD ($)
Short-Term Borrowings [Abstract]
Short-term borrowings	$ 25,772		$ 25,772			$ 13,753
Interest expense related to short-term borrowings	228	$ 194	339	$ 333
Line of Credit Due on January 23, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	0		$ 0			5,057
Maximum borrowing capacity \| ¥					¥ 50,000
Annual interest rate			5.22%
Line of credit due date			Jan. 23, 2020
Line of Credit Due on February 21, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	0		$ 0			1,433
Maximum borrowing capacity \| ¥					20,000
Annual interest rate			5.66%
Line of credit due date			Feb. 21, 2020
Line of Credit Due on January 18, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	0		$ 0			1,433
Maximum borrowing capacity \| ¥					20,000
Annual interest rate			5.66%
Line of credit due date			Jan. 19, 2020
Line of Credit Due on January 22, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	0		$ 0			717
Maximum borrowing capacity \| ¥					20,000
Annual interest rate			5.66%
Line of credit due date			Jan. 22, 2020
Line of Credit Due on February 14, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	0		$ 0			717
Maximum borrowing capacity \| ¥					20,000
Annual interest rate			5.66%
Line of credit due date			Feb. 14, 2020
Line of Credit Due on March 25, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	0		$ 0			3,250
Maximum borrowing capacity \| ¥					50,000
Annual interest rate			4.94%
Line of credit due date			Mar. 24, 2020
Line of Credit Due on April 17, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	0		$ 0			$ 1,146
Maximum borrowing capacity \| ¥					50,000
Annual interest rate			5.66%
Line of credit due date			Apr. 02, 2020
Line of Credit Due on August 24, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	2,685		$ 2,685
Maximum borrowing capacity \| ¥					50,000
Annual interest rate			5.22%
Line of credit due date			Aug. 24, 2020
Line of Credit Due on April 1, 2021 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	4,239		$ 4,239
Maximum borrowing capacity \| ¥					80,000
Annual interest rate			4.70%
Line of credit due date			Apr. 01, 2021
Line of Credit Due on June 27, 2021 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	1,272		$ 1,272
Maximum borrowing capacity \| ¥					80,000
Annual interest rate			4.25%
Line of credit due date			Jun. 27, 2021
Line of Credit Due on April 29, 2021 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	820		$ 820
Maximum borrowing capacity \| ¥					80,000
Annual interest rate			2.80%
Line of credit due date			Apr. 29, 2021
Line of Credit Due on June 27, 2021 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	2,081		$ 2,081
Maximum borrowing capacity \| ¥					80,000
Annual interest rate			2.70%
Line of credit due date			Jun. 27, 2021
Line of Credit Due on April 12, 2021 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	1,413		$ 1,413
Maximum borrowing capacity \| ¥					20,000
Annual interest rate			4.65%
Line of credit due date			Apr. 12, 2021
Line of Credit Due on May 24, 2021 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	1,413		$ 1,413
Maximum borrowing capacity \| ¥					20,000
Annual interest rate			3.65%
Line of credit due date			May 24, 2021
Line of Credit Due on May 27, 2021 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	2,374		$ 2,374
Maximum borrowing capacity \| ¥					70,000
Annual interest rate			4.68%
Line of credit due date			May 27, 2021
Line of Credit Due on June 27, 2021 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	1,272		$ 1,272
Maximum borrowing capacity \| ¥					70,000
Annual interest rate			4.68%
Line of credit due date			Jun. 27, 2021
Line of Credit Due on May 28, 2021 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	2,442		$ 2,442
Maximum borrowing capacity \| ¥					70,000
Annual interest rate			3.48%
Line of credit due date			May 28, 2021
Line of Credit Due on June 7, 2021 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	1,521		$ 1,521
Maximum borrowing capacity \| ¥					70,000
Annual interest rate			3.50%
Line of credit due date			Jun. 07, 2021
Line of Credit Due on June 16, 2021 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	1,838		$ 1,838
Maximum borrowing capacity \| ¥					70,000
Annual interest rate			3.50%
Line of credit due date			Jun. 16, 2021
Line of Credit Due on December 17, 2020 [Member]
Short-Term Borrowings [Abstract]
Short-term borrowings	$ 2,402		$ 2,402
Maximum borrowing capacity \| ¥					¥ 30,000
Annual interest rate			4.35%
Line of credit due date			Dec. 17, 2020

OTHER PAYABLE AND ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
OTHER PAYABLE AND ACCRUED EXPENSES [Abstract]
Accrued commissions	$ 5,720	$ 4,082
Accrued warranty	3,284	2,811
Accrued payroll	1,907	2,092
Accrued professional fees	66	165
Accrued machine testing fees	1,426	1,456
Others	2,954	2,268
Total	$ 15,357	$ 12,874

LEASES (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
LEASES (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Components of lease expense [Abstract]
Operating lease cost	$ 378	$ 264	$ 755	$ 701
Short-term lease cost	47	7	97	25
Lease cost	425	271	852	726
Cash paid for amounts included in the measurement of lease liabilities [Abstract]
Operating cash outflow from operating leases	425	$ 271	852	$ 726
Maturities of lease liabilities [Abstract]
2020	755		755
2021	1,496		1,496
2022	1,496		1,496
2023	874		874
2024	834		834
Total lease payments	5,455		5,455
Less: interest	(807)		(807)
Present value of lease liabilities	$ 4,648		$ 4,648
Weighted average remaining lease terms and discount rates [Abstract]
Weighted average remaining lease term	2 years 4 months 13 days		2 years 4 months 13 days		3 years 7 days
Weighted average discount rate	5.29%		5.29%		5.43%

OTHER LONG-TERM LIABILITIES (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Other Long-term Liabilities [Abstract]
Other long-term liabilities	$ 6,584	$ 4,186
Subsidies to Stress Free Polishing Project, Commenced in 2008 and 2017 [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	1,136	1,251
Subsidies to Electro Copper Plating Project, Commenced in 2014 [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	2,339	2,666
Subsidies to Polytetrafluoroethylene, Commenced in 2018 [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	120	135
Subsidies to Tahoe-Single Bench Clean, Commenced in 2020 [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	1,913	0
Subsidies to Backside Clean-YMTC National Project, Commenced in 2020
Other Long-term Liabilities [Abstract]
Other long-term liabilities	834	0
Other [Member]
Other Long-term Liabilities [Abstract]
Other long-term liabilities	$ 242	$ 134

LONG-TERM INVESTMENT (Details) $ / shares in Units, $ in Thousands, ¥ in Millions	Sep. 05, 2019 shares	Jun. 30, 2020 USD ($)	Jun. 18, 2020 USD ($)	Jun. 18, 2020 CNY (¥)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 27, 2019 USD ($)	Sep. 11, 2017 USD ($) $ / shares shares
Classification of Investments [Abstract]
Total		$ 20,360			$ 5,934
Ninebell [Member]
Investments [Abstract]
Percentage of ordinary shares issued								20.00%
Purchase price								$ 1,200
Classification of Investments [Abstract]
Total		1,891			1,538
Ninebell [Member] \| Class A Common Stock [Member]
Investments [Abstract]
Purchase price								$ 1,000
Shares issued (in shares) \| shares								133,334
Share price (in dollars per share) \| $ / shares								$ 7.50
Shengyi [Member]
Investments [Abstract]
Percentage of ordinary shares issued							15.00%
Number of investors with agreements entered \| shares	6
Investment - equity method							$ 109
Classification of Investments [Abstract]
Total		128			107
Hefei Shixi [Member]
Investments [Abstract]
Investment in partnership						$ 4,200
Ownership percentage in partnership						10.00%
Classification of Investments [Abstract]
Total		4,211			4,289
Qingdao LP [Member]
Investments [Abstract]
Investment in partnership			$ 14,200	¥ 100
Ownership percentage in partnership			4.30%	4.30%
Total capital fund of limited partnership			$ 315,000	¥ 2,224
Classification of Investments [Abstract]
Total		$ 14,130			$ 0
SMIC [Member] \| Minimum [Member]
Investments [Abstract]
Ownership percentage in partnership		30.00%

FINANCIAL LIABILITY CARRIED AT FAIR VALUE (Details) $ / shares in Units, ¥ in Thousands, $ in Thousands	1 Months Ended				3 Months Ended		6 Months Ended
	Apr. 30, 2020 USD ($) Agreement shares	Aug. 31, 2019 USD ($) $ / shares shares	Mar. 31, 2018 USD ($) shares	Mar. 31, 2017 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) shares	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) shares	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 CNY (¥)
Related Party Transaction [Abstract]
Financial liability carried at fair value					$ 15,147		$ 15,147		$ 0
Change in fair value of financial liability					5,431	$ 0	5,431	$ 0
Senior Secured Promissory Note [Member] \| Other Receivables [Member]
Related Party Transaction [Abstract]
Receivables					$ 1,820		$ 1,820
Common Class A [Member]
Related Party Transaction [Abstract]
Stock price (in dollars per share) \| $ / shares		$ 13.195
ACM Shanghai [Member]
Related Party Transaction [Abstract]
Repayments of notes		$ 1,161
Number of agreement \| Agreement	2
ACM Shanghai [Member] \| Senior Secured Promissory Note [Member]
Related Party Transaction [Abstract]
Receivables	$ 1,820
ACM Shanghai [Member] \| Intercompany Note [Member]
Related Party Transaction [Abstract]
Promissory note principal amount			$ 2,981
Interest rate on promissory note			3.01%
Promissory note maturity date							Aug. 17, 2023
Cancellation of outstanding obligation, amount	$ 1,820
SMC [Member]
Related Party Transaction [Abstract]
Payment for investment										$ 2,981	¥ 20,123,500
Stock price (in dollars per share) \| $ / shares		$ 13.195
Investment repayment period							60 days
Number of shares repurchased/surrender in exchange (in shares) \| shares	242,681	154,821
Repayments of notes		$ 882
Investment due amount		1,820
Consideration price in fair value	$ 9,716
SMC [Member] \| Senior Secured Promissory Note [Member]
Related Party Transaction [Abstract]
Promissory note principal amount			$ 2,981
Interest rate on promissory note			3.01%
Promissory note maturity date							Aug. 17, 2023
SMC [Member] \| Common Class A [Member]
Related Party Transaction [Abstract]
Shares issued (in shares) \| shares				397,502
Shares issued value				$ 2,981
Stock price (in dollars per share) \| $ / shares				$ 7.50
Number of shares repurchased/surrender in exchange (in shares) \| shares					242,681		242,681
SMC [Member] \| Common Class A [Member] \| Senior Secured Promissory Note [Member]
Related Party Transaction [Abstract]
Exercise of common stock warrant issued (in shares) \| shares			397,502
SMC [Member] \| ACM Shanghai [Member]
Related Party Transaction [Abstract]
Repayment of investment in cash	$ 1,820	$ 1,161

RELATED PARTY BALANCES AND TRANSACTIONS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Related Party Transaction [Abstract]
Accounts payable	$ 2,789		$ 2,789		$ 1,215
Purchase of materials	3,826	$ 2,675	6,037	$ 4,995
Ninebell Co., Ltd [Member]
Related Party Transaction [Abstract]
Prepaid expenses	878		878		348
Accounts payable	2,261		2,261		727
Purchase of materials	3,370	2,483	5,523	4,803
Shengyi Semiconductor Technology Co., Ltd [Member]
Related Party Transaction [Abstract]
Accounts payable	528		528		$ 488
Purchase of materials	456	192	514	192
Service fee charged by	$ 144	$ 0	$ 190	$ 0

COMMON STOCK (Details)	1 Months Ended		3 Months Ended		6 Months Ended
COMMON STOCK (Details)	Apr. 30, 2020 shares	Aug. 31, 2019 shares	Jun. 30, 2020 Vote $ / shares shares	Jun. 30, 2019 shares	Jun. 30, 2020 Vote $ / shares shares	Jun. 30, 2019 shares	Dec. 31, 2019 $ / shares shares
Class of Stock [Abstract]
Number of shares cancelled (in shares)			242,681		242,681
SMC [Member]
Class of Stock [Abstract]
Stock repurchase (in shares)	242,681	154,821
Common Class A [Member]
Class of Stock [Abstract]
Common stock, shares authorized (in shares)			50,000,000		50,000,000		50,000,000
Common stock, par value (in dollars per share) \| $ / shares			$ 0.0001		$ 0.0001		$ 0.0001
Number of votes for each share entitled \| Vote			1		1
Common stock, shares issued (in shares)			16,250,092		16,250,092		16,182,151
Common stock, shares outstanding (in shares)			16,250,092		16,250,092		16,182,151
Common Class A [Member] \| SMC [Member]
Class of Stock [Abstract]
Stock repurchase (in shares)			242,681		242,681
Common Class A [Member] \| Common Stock [Member]
Class of Stock [Abstract]
Exercise of common stock warrant issued (in shares)					64,717
Stock issued upon exercise of stock options (in shares)			115,425	38,252	185,903	104,627
Stock repurchase (in shares)			242,681		242,681
Common Class B [Member]
Class of Stock [Abstract]
Common stock, shares authorized (in shares)			2,409,738		2,409,738		2,409,738
Common stock, par value (in dollars per share) \| $ / shares			$ 0.0001		$ 0.0001		$ 0.0001
Number of votes for each share entitled \| Vote			20		20
Convertible shares in to Class A common stock (in shares)					1
Common stock, shares issued (in shares)			1,802,606		1,802,606		1,862,608
Common stock, shares outstanding (in shares)			1,802,606		1,802,606		1,862,608
Common Class B [Member] \| Common Stock [Member]
Class of Stock [Abstract]
Exercise of common stock warrant issued (in shares)					0
Stock issued upon exercise of stock options (in shares)			0	0	0	0
Stock repurchase (in shares)			0		0

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

STOCK-BASED COMPENSATION, Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	$ 855	$ 618	$ 1,544	$ 1,362
Employee Stock Purchase Plan [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	635	291	1,066	512
Employee Stock Purchase Plan [Member] \| ACM Shanghai [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	80	0	166	0
Non-Employee Stock Purchase Plan [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	140	327	312	850
Cost of Revenue [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	43	29	88	59
Sales and Marketing Expense [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	164	46	258	80
Research and Development Expense [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	188	94	375	180
General and Administrative Expense [Member]
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	$ 460	$ 449	$ 823	$ 1,043

STOCK-BASED COMPENSATION, Share Option Activities (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Weighed Average Remaining Contractual Term [Abstract]
Stock-based compensation expense	$ 855	$ 618	$ 1,544	$ 1,362
Employee Share Option [Member]
Number of Option Share [Roll Forward]
Outstanding, beginning of period (in shares)			2,994,063
Granted (in shares)			708,399
Exercised (in shares)			(41,172)
Expired (in shares)			0
Forfeited/cancelled (in shares)			(39,120)
Outstanding, end of period (in shares)	3,622,170		3,622,170		2,994,063
Vested and exercisable (in shares)	1,997,526		1,997,526
Weighted Average Grant Date Fair Value [Abstract]
Outstanding at beginning of period (in dollars per share)			$ 2.59
Granted (in dollars per share)			9.88
Exercised (in dollars per share)			2.71
Expired (in dollars per share)			0
Forfeited/cancelled (in dollars per share)			5.10
Outstanding at end of period (in dollars per share)	$ 3.98		3.98		$ 2.59
Weighted Average Exercise Price [Abstract]
Outstanding, beginning of period (in dollars per share)			6.77
Granted (in dollars per share)			24.13
Exercised (in dollars per share)			6.47
Expired (in dollars per share)			0
Forfeited/cancelled (in dollars per share)			13.46
Outstanding, end of period (in dollars per share)	$ 10.10		$ 10.10		$ 6.77
Weighed Average Remaining Contractual Term [Abstract]
Outstanding weighed average remaining contractual term			7 years 1 month 28 days		7 years 18 days
Stock-based compensation expense	$ 635	291	$ 1,066	512
Unrecognized employee stock-based compensation expense	$ 10,252		$ 10,252		$ 4,712
Weighted-average period over which unrecognized compensation is expected to be recognized			2 years 5 months 8 days		1 year 5 months 19 days
Employee Share Option [Member] \| ACM Shanghai [Member]
Number of Option Share [Roll Forward]
Outstanding, beginning of period (in shares)			0
Granted (in shares)			5,869,808
Exercised (in shares)			0
Expired (in shares)			0
Forfeited/cancelled (in shares)			(330,770)
Outstanding, end of period (in shares)	5,539,038		5,539,038		0
Vested and exercisable (in shares)	0		0
Weighted Average Grant Date Fair Value [Abstract]
Outstanding at beginning of period (in dollars per share)			$ 0
Granted (in dollars per share)			0.22
Exercised (in dollars per share)			0
Expired (in dollars per share)			0
Forfeited/cancelled (in dollars per share)			0.23
Outstanding at end of period (in dollars per share)	$ 0.22		0.22		$ 0
Weighted Average Exercise Price [Abstract]
Outstanding, beginning of period (in dollars per share)			0
Granted (in dollars per share)			1.87
Exercised (in dollars per share)			0
Expired (in dollars per share)			0
Forfeited/cancelled (in dollars per share)			1.87
Outstanding, end of period (in dollars per share)	$ 1.87		$ 1.87		$ 0
Weighed Average Remaining Contractual Term [Abstract]
Outstanding weighed average remaining contractual term			4 years 3 days		0 years
Stock-based compensation expense	$ 80	0	$ 166	0
Non-Employee Stock Option [Member]
Number of Option Share [Roll Forward]
Outstanding, beginning of period (in shares)			1,101,613
Granted (in shares)			20,000
Exercised (in shares)			(144,731)
Expired (in shares)			0
Forfeited/cancelled (in shares)			0
Outstanding, end of period (in shares)	976,882		976,882		1,101,613
Vested and exercisable (in shares)	929,397		929,397
Weighted Average Grant Date Fair Value [Abstract]
Outstanding at beginning of period (in dollars per share)			$ 0.82
Granted (in dollars per share)			10.29
Exercised (in dollars per share)			1.22
Outstanding at end of period (in dollars per share)	$ 0.95		0.95		$ 0.82
Weighted Average Exercise Price [Abstract]
Outstanding, beginning of period (in dollars per share)			2.69
Granted (in dollars per share)			25.60
Exercised (in dollars per share)			4.19
Outstanding, end of period (in dollars per share)	$ 2.93		$ 2.93		$ 2.69
Weighed Average Remaining Contractual Term [Abstract]
Outstanding weighed average remaining contractual term			5 years 4 months 20 days		5 years 10 months 6 days
Stock-based compensation expense	$ 140	$ 327	$ 312	$ 850
Unrecognized employee stock-based compensation expense	279		$ 279		$ 406
Weighted-average period over which unrecognized compensation is expected to be recognized			1 month 17 days		2 months 23 days
Non-Employee Stock Option [Member] \| ACM Shanghai [Member]
Weighed Average Remaining Contractual Term [Abstract]
Unrecognized employee stock-based compensation expense	$ 989		$ 989
Weighted-average period over which unrecognized compensation is expected to be recognized			3 years 3 days

STOCK-BASED COMPENSATION, Assumptions Used to Determine Fair Value of Share Options Granted (Details)

6 Months Ended

Jun. 30, 2020

$ / shares

Employee Share Option [Member] | Market Based [Member]

Fair value of common share (in dollars per share)

$ 22.07

^[1]

Volatility

45.10%

^[2]

Risk-free interest rate

2.68%

^[3]

Expected dividend

0.00%

^[4]

Employee Share Option [Member] | Market Based [Member] | Minimum [Member]

Employee Share Option [Member] | Market Based [Member] | Maximum [Member]

9 years 2 months 12 days

^[5]

Employee and Non-employee Stock Option [Member] | Service Period Based [Member]

9 years 9 months 18 days

^[5]

Employee and Non-employee Stock Option [Member] | Service Period Based [Member] | Minimum [Member]

Expected dividend

0.00%

^[4]

Fair value of common share (in dollars per share)

$ 22.07

^[1]

Employee and Non-employee Stock Option [Member] | Service Period Based [Member] | Maximum [Member]

5 years 6 months

^[5]

Volatility

42.17%

^[2]

Risk-free interest rate

0.51%

^[3]

Fair value of common share (in dollars per share)

$ 38.26

^[1]