Segments and Major Customers (Details 3) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Major Customer Disclosure
Revenues	$ 48,384	$ 46,426
TAIWAN, PROVINCE OF CHINA
Major Customer Disclosure
Revenues	2,101	16,110
South Korea
Major Customer Disclosure
Revenues	1,281	8,601
USA
Major Customer Disclosure
Revenues	34,239	11,221
Japan
Major Customer Disclosure
Revenues	2,619	4,034
Europe
Major Customer Disclosure
Revenues	3,375	3,866
Canada
Major Customer Disclosure
Revenues	1,058	1,410
SINGAPORE
Major Customer Disclosure
Revenues	1,884	92
Asia-Other
Major Customer Disclosure
Revenues	$ 1,827	$ 1,092