STOCK-BASED COMPENSATION - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	$ 10,581	$ 1,893	$ 14,666	$ 5,236
Employee Stock Option Plan
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	2,352	1,798	6,345	4,943
Employee Stock Option Plan | ACM Shanghai
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	8,217	83	8,286	258
Non-Employee Stock Option Plan
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	12	12	35	35
Cost of revenue
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	588	130	838	383
Sales and marketing expense
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	2,543	349	3,405	1,277
Research and development expense
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	3,421	666	4,831	1,733
General and administrative expense
Stock-based Compensation Expense [Abstract]
Stock-based compensation expense	$ 4,029	$ 748	$ 5,592	$ 1,843