Segments and Major Customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Financial information of business segments
Revenues	$ 48,384	$ 46,426
Segment operating expenses	40,683	41,365
Segment reconciling items	(39,110)	(48,674)
Operating income (loss)	(31,409)	(43,613)
Interest and other income (expense), net	5,142	4,695
Income (Loss) before income taxes	(26,267)	(38,918)
MID Segment
Financial information of business segments
Revenues	34,490	33,967
Segment operating expenses	23,979	22,949
Segment Operating Income (Loss)	10,511	11,018
RSD Segment
Financial information of business segments
Revenues	13,894	10,018
Segment operating expenses	14,221	12,786
Segment Operating Income (Loss)	(327)	(2,768)
Other
Financial information of business segments
Revenues	0	2,441
Segment operating expenses	2,483	5,630
Segment Operating Income (Loss)	(2,483)	(3,189)
Operating Segments [Member]
Financial information of business segments
Segment Operating Income (Loss)	$ 7,701	$ 5,061