Related Party Balances and Transactions	3 Months Ended
Mar. 31, 2018
Related Party Transactions [Abstract]
Related Party Balances and Transactions	On August 18, 2017, ACM and Ninebell, its equity method investment affiliate (note 10), entered into a loan agreement pursuant to which ACM made an interest-free loan of $946 to Ninebell, payable in 180 days or automatically extended another 180 days if in default. The loan was secured by a pledge of Ninebell’s accounts receivable due from ACM and all money that Ninebell received from ACM. Ninebell repaid the loan in March 2018. During the three months ended March 31, 2018 and 2017, ACM purchased materials from Ninebell amounting to $970 and $840, respectively. As of March 31, 2018 and December 31, 2017, accounts payable due to Ninebell was $350 and $2,118, respectively. In 2007 ACM Shanghai entered into an operating lease agreement with Shanghai Zhangjiang Group Co., Ltd. (“Zhangjiang Group”) to lease manufacturing and office space located in Shanghai, China. An affiliate of Zhangjiang Group holds 787,098 shares of Class A common stock that it acquired in September 2017 for $5,903. Pursuant to the lease agreement, Zhangjiang Group provided $771 to ACM Shanghai for leasehold improvements. In September 2016 the lease agreement was amended to modify payment terms and extend the lease through December 31, 2017. As of March 31, 2018, ACM Shanghai was leasing the property on a month-to-month basis. On April 26, 2018, ACM Shanghai renewed the operating lease, effective as of January 1, 2018 and continuing through December 31, 2022. During the first year, monthly payments are RMB 366, effective January 1, 2018. The required security deposit is RMB 1,077. During the three months ended March 31, 2018 and 2017, the Company incurred leasing expenses under the lease agreement of $172 and $159, respectively. As of March 31, 2018 and December 31, 2017, payables to Zhangjiang Group for lease expenses and leasehold improvements recorded as other payables and accrued expenses amounted to $2,248 and $2,024, respectively (note 7). On December 9, 2016, ACM Shanghai received the SMC Investment from SMC for potential investment pursuant to terms to be subsequently negotiated (note 8). SMC is a limited partnership incorporated in the PRC, whose partners consist of employees of ACM Shanghai. On March 14, 2017, ACM, ACM Shanghai and SMC entered into a securities purchase agreement (the “SMC Agreement”) pursuant to which, in exchange for the SMC Investment, ACM issued to SMC a warrant exercisable, for cash or on a cashless basis, to purchase, at any time on or before May 17, 2023, all, but not less than all, of 397,502 shares of Class A common stock at a price of $7.50 per share, for a total exercise price of $2,981. On March 30, 2018, SMC exercised the warrant and purchased 397,502 shares of Class A common stock (note 8).

Related Party Balances and Transactions

3 Months Ended

Mar. 31, 2018

On August 18, 2017, ACM and Ninebell, its equity method investment affiliate (note 10), entered into a loan agreement pursuant to which ACM made an interest-free loan of $946 to Ninebell, payable in 180 days or automatically extended another 180 days if in default. The loan was secured by a pledge of Ninebell’s accounts receivable due from ACM and all money that Ninebell received from ACM. Ninebell repaid the loan in March 2018. During the three months ended March 31, 2018 and 2017, ACM purchased materials from Ninebell amounting to $970 and $840, respectively. As of March 31, 2018 and December 31, 2017, accounts payable due to Ninebell was $350 and $2,118, respectively.

In 2007 ACM Shanghai entered into an operating lease agreement with Shanghai Zhangjiang Group Co., Ltd. (“Zhangjiang Group”) to lease manufacturing and office space located in Shanghai, China. An affiliate of Zhangjiang Group holds 787,098 shares of Class A common stock that it acquired in September 2017 for $5,903. Pursuant to the lease agreement, Zhangjiang Group provided $771 to ACM Shanghai for leasehold improvements. In September 2016 the lease agreement was amended to modify payment terms and extend the lease through December 31, 2017. As of March 31, 2018, ACM Shanghai was leasing the property on a month-to-month basis. On April 26, 2018, ACM Shanghai renewed the operating lease, effective as of January 1, 2018 and continuing through December 31, 2022. During the first year, monthly payments are RMB 366, effective January 1, 2018. The required security deposit is RMB 1,077. During the three months ended March 31, 2018 and 2017, the Company incurred leasing expenses under the lease agreement of $172 and $159, respectively. As of March 31, 2018 and December 31, 2017, payables to Zhangjiang Group for lease expenses and leasehold improvements recorded as other payables and accrued expenses amounted to $2,248 and $2,024, respectively (note 7).

On December 9, 2016, ACM Shanghai received the SMC Investment from SMC for potential investment pursuant to terms to be subsequently negotiated (note 8). SMC is a limited partnership incorporated in the PRC, whose partners consist of employees of ACM Shanghai. On March 14, 2017, ACM, ACM Shanghai and SMC entered into a securities purchase agreement (the “SMC Agreement”) pursuant to which, in exchange for the SMC Investment, ACM issued to SMC a warrant exercisable, for cash or on a cashless basis, to purchase, at any time on or before May 17, 2023, all, but not less than all, of 397,502 shares of Class A common stock at a price of $7.50 per share, for a total exercise price of $2,981. On March 30, 2018, SMC exercised the warrant and purchased 397,502 shares of Class A common stock (note 8).