SIGNIFICANT ACCOUNTING POLICIES, Basic and Diluted Net Income per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator [Abstract]
Net income	$ 10,020	$ 9,089	$ 12,479	$ 15,257
Net income attributable to non-controlling interests and redeemable non-controlling interests	1,393	307	2,228	307
Net income attributable to ACM Research, Inc.	$ 8,627	$ 8,782	$ 10,251	$ 14,950
Weighted average shares outstanding, basic (in shares)	18,201,943	16,999,746	18,124,665	16,381,944
Effect of dilutive securities (in shares)	3,353,353	2,354,468	3,132,996	2,317,066
Weighted average shares outstanding, diluted (in shares)	21,555,296	19,354,214	21,257,661	18,699,010
Net income per common share:
Basic (in dollars per share)	$ 0.47	$ 0.52	$ 0.57	$ 0.91
Diluted (in dollars per share)	$ 0.40	$ 0.45	$ 0.48	$ 0.80