Segments and Major Customers (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Financial information of business segments
Revenues	$ 94,720	$ 76,501	$ 192,071	$ 149,183
Segment operating expenses	44,669	33,426	86,058	64,505
Segment reconciling items	(41,807)	(31,067)	(84,335)	(63,376)
Operating income (loss)	8,244	12,008	21,678	21,302
Interest and other income (expense), net	(3,132)	(2,025)	(6,184)	(4,924)
Income (Loss) before income taxes	5,112	9,983	15,494	16,378
MID Segment
Financial information of business segments
Revenues	67,402	54,467	137,997	108,012
Segment operating expenses	23,801	13,229	44,056	25,272
Segment Operating Income (Loss)	43,601	41,238	93,941	82,740
RSD Segment
Financial information of business segments
Revenues	23,366	16,407	46,571	30,508
Segment operating expenses	12,214	13,105	24,613	25,015
Segment Operating Income (Loss)	11,152	3,302	21,958	5,493
Other
Financial information of business segments
Revenues	3,952	5,627	7,503	10,663
Segment operating expenses	8,654	7,092	17,389	14,218
Segment Operating Income (Loss)	(4,702)	(1,465)	(9,886)	(3,555)
Operating Segments [Member]
Financial information of business segments
Segment Operating Income (Loss)	$ 50,051	$ 43,075	$ 106,013	$ 84,678