Segments and Major Customers (Details 3) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Major Customer Disclosure
Revenue	$ 57,399	$ 59,754	$ 164,080	$ 162,638
TAIWAN, PROVINCE OF CHINA
Major Customer Disclosure
Revenue	4,186	3,962	19,047	20,419
South Korea
Major Customer Disclosure
Revenue	738	388	2,777	10,656
USA
Major Customer Disclosure
Revenue	33,218	37,899	97,421	78,983
Japan
Major Customer Disclosure
Revenue	3,419	3,889	8,565	20,201
Europe
Major Customer Disclosure
Revenue	2,846	4,156	8,861	11,628
Canada
Major Customer Disclosure
Revenue	896	820	3,377	4,115
SINGAPORE
Major Customer Disclosure
Revenue	7,695	7,953	14,304	14,103
Asia-Other
Major Customer Disclosure
Revenue	$ 4,401	$ 687	$ 9,728	$ 2,533