SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash, cash equivalents and restricted cash and time deposits	$ 207,101		$ 207,101		$ 247,951
Short-term and long-term time deposits	118,834		118,834		172,448
ACM Shanghai
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash payments for procurement of goods and services	10,724	$ 12,682	35,195	$ 24,631
United States
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash, cash equivalents and restricted cash and time deposits	36,251		36,251		25,011
Mainland China
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash, cash equivalents and restricted cash and time deposits	109,992		109,992		129,695
China Hong Kong
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash, cash equivalents and restricted cash and time deposits	56,731		56,731		89,187
Korea
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash, cash equivalents and restricted cash and time deposits	4,060		4,060		4,007
Singapore
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash, cash equivalents and restricted cash and time deposits	$ 67		$ 67		$ 51