FINANCIAL LIABILITY CARRIED AT FAIR VALUE (Details) $ / shares in Units, ¥ in Thousands, $ in Thousands					1 Months Ended				12 Months Ended
		Jun. 09, 2021 USD ($) shares	Jul. 29, 2020 USD ($) $ / shares shares	Mar. 30, 2018 shares	Apr. 30, 2020 USD ($) Agreement shares	Aug. 31, 2019 USD ($) $ / shares shares	Mar. 31, 2018 USD ($) shares	Mar. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 CNY (¥)
Related Party Transaction [Abstract]
Shares issued value											$ 26,435
Change in fair value of financial liability									$ 0	$ 11,964	0
Issuance of warrant for settlement of financial liability									0	$ 19,859	$ 0
SMC 2020 Warrants [Member]
Related Party Transaction [Abstract]
Financial liability carried at fair value			$ 21,679
Change in fair value of financial liability									11,964
Fair value warrant amount									$ 21,679
Fair Value of Options Granted [Abstract]
Fair value of common share (in dollars per share) | $ / shares	[1]		$ 89.28
Expected term	[2]		3 years 5 months 1 day
Volatility	[3]		47.42%
Expected dividend	[4]		0.15%
Risk-free interest rate	[5]		0.00%
Common Class A [Member]
Related Party Transaction [Abstract]
Shares issued (in shares) | shares						2,053,572
Fair Value of Options Granted [Abstract]
Fair value of common share (in dollars per share) | $ / shares						$ 14.00
Common Class A [Member] | SMC 2020 Warrants [Member]
Related Party Transaction [Abstract]
Shares issued (in shares) | shares		242,681	242,681							242,681
Shares issued value		$ 1,820
Fair Value of Options Granted [Abstract]
Fair value of common share (in dollars per share) | $ / shares			$ 7.50
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
Fair value warrant amount					$ 1,820
SMC [Member]
Related Party Transaction [Abstract]
Payment for investment												$ 2,981	¥ 20,123,500
Investment repayment period									60 days
Number of shares repurchased/surrender in exchange (in shares) | shares					242,681	154,821
Repayments of notes						$ 882
Investment due amount						$ 1,820
Consideration price in fair value					$ 9,715
Issuance of warrant for settlement of financial liability									$ 19,859
Fair Value of Options Granted [Abstract]
Fair value of common share (in dollars per share) | $ / shares						$ 13.195
SMC [Member] | Senior Secured Promissory Note [Member]
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
Exercise of common stock warrant issued (in shares) | shares				397,502
Fair Value of Options Granted [Abstract]
Fair value of common share (in dollars per share) | $ / shares						$ 13.195		$ 7.50
SMC [Member] | Common Class A [Member] | Senior Secured Promissory Note [Member]
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

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

[2] Expected term of share options 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 the stock of companies comparable to ACM in the period equal to the expected term of each grant.

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

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