Segment Information (Details 3) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Major customer disclosure
Revenue	$ 56,915	$ 57,399	$ 180,834	$ 164,080
USA
Major customer disclosure
Revenue	29,068	33,218	95,870	97,421
Taiwan
Major customer disclosure
Revenue	8,234	4,186	19,050	19,047
South Korea
Major customer disclosure
Revenue	719	738	3,240	2,777
Japan
Major customer disclosure
Revenue	4,175	3,419	13,174	8,565
Europe
Major customer disclosure
Revenue	728	2,846	6,410	8,861
Canada
Major customer disclosure
Revenue	534	896	1,077	3,377
Singapore
Major customer disclosure
Revenue	6,754	7,695	23,186	14,304
Asia-Other
Major customer disclosure
Revenue	$ 6,703	$ 4,401	$ 18,827	$ 9,728