LONG-TERM INVESTMENT (Tables)

9 Months Ended

Sep. 30, 2023

Long-Term Investments [Abstract]

Long-Term Investment

Equity method investee:	Initial investment dates	Investment entity	Percent ownership by ACM and subsidiaries	Investment purchase price
Ninebell Co., Ltd. ("Ninebell")	September 2017	ACM	20%	$	1,200
Wooil Flucon Co. ("Wooil")	August 2022	ACM Singapore	20%	$	1,000
Shengyi Semiconductor Technology Co., Ltd. (“Shengyi”)	June 2019	ACM Shanghai	14%	$	109
Hefei Shixi Chanheng Integrated Circuit Industry Venture Capital Fund Partnership (LP) (“Hefei Shixi”)	September 2019	ACM Shanghai	10%	RMB 30,000 ($4,200)

Equity method investee:	September 30, 2023		December 31, 2022
Ninebell	$	5,476	$	5,199
Wooil	1,004		1,011
Shengyi	1,798		1,168
Hefei Shixi	6,148		8,645
Subtotal	14,426		16,023
Investments accounted for using measurement alternative:
Waferworks (Shanghai) Co., Ltd	1,392		1,436
Shengyi	846		—
Other	5,642		—
Total	22,306		17,459