COMMITMENTS AND CONTINGENCIES	3 Months Ended
COMMITMENTS AND CONTINGENCIES	Mar. 31, 2021
COMMITMENTS AND CONTINGENCIES [Abstract]
COMMITMENTS AND CONTINGENCIES	NOTE 21 – COMMITMENTS AND CONTINGENCIES The Company leases offices under non-cancelable operating lease agreements. See note 8 for future minimum lease payments under non-cancelable operating lease agreements with initial terms of one year or more. As of March 31, 2021, the Company had $3,429 of open capital commitments. Covenants in ACM Shengwei’s Grant Contract for State-owned Construction Land Use Right in Shanghai City with the China (Shanghai) Pilot Free Trade Zone Lingang Special Area Administration require, among other things, that ACM Shengwei pay liquidated damages in the event that (a) it does not make a total investment (including the costs of construction, fixtures, equipment and grant fees) of at least RMB 450.0 million ($63,400) or (b) within six years after the land use right is obtained, the Company does not (i) generate a minimum specified amount of annual sales of products manufactured on the granted land or (ii) pay to the PRC at least RMB 157.6 million ($22,000) in annual total taxes (including value-added taxes, corporate income tax, personal income taxes, urban maintenance and construction taxes, education surcharges, stamp taxes, and vehicle and shipping taxes) as a result of operations in connection with the granted land. As of March 31, 2021, the Company had paid in total $10,328 for its Lingang-related investments. In the normal course of business, the Company is subject to contingencies, including legal proceedings and environmental claims arising out of the normal course of businesses that relate to a wide range of matters, including among others, contracts breach liability. The Company records accruals for such contingencies based upon the assessment of the probability of occurrence and, where determinable, an estimate of the liability. Management may consider many factors in making these assessments including past history, scientific evidence and the specifics of each matter. Some of these contingencies involve claims that are subject to substantial uncertainties and unascertainable damages. The Company’s management has evaluated all such proceedings and claims that existed as of March 31, 2021 and December 31, 2020. In the opinion of management, no provision for liability nor disclosure was required as of March 31, 2021 related to any claim against the Company because: (a) there is not a reasonable possibility that a loss exceeding amounts already recognized (if any) may be incurred with respect to such claim; (b) a reasonably possible loss or range of loss cannot be estimated; or (c) such estimate is immaterial. As of March 31, 2021, the Company had one outstanding legal proceeding. On December 21, 2020, a putative class action lawsuit against ACM and three of its officers was filed in the U.S. District Court for the Northern District of California under the caption Kain v. ACM Research, Inc., et al., No. 3:20-cv-09241. The complaint alleges claims under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder, and seeks monetary damages in an unspecified amount as well as costs and expenses incurred in the litigation. On April 15, 2021, the court appointed Mr. Kain as lead plaintiff, finding that no better-suited candidates emerged during the statutory sixty-day period following public notice of the lawsuit. ACM’s management believes the claims are without merit and intend to vigorously defend this litigation. The Company is currently unable to predict the outcome of this lawsuit and therefore cannot determine the likelihood of loss or estimate a range of possible loss.