Accumulated Other Comprehensive Income or Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Equity [Abstract]
Net unrealized gain on available-for-sale investments				$ 6,736	$ 5,065
Foreign currency translation				(75)	(104)
Accumulated other comprehensive income	$ 4,961	$ 4,717	$ 232	6,661	4,961
Deferred tax liability				$ 3,600	$ 2,800
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income - January 1	4,961	4,717	232
Unrealized gain reclassified and recognized in net loss, net of tax	(193)	(481)	(3,020)
Foreign exchange reclassified and recognized in net loss, net of tax	20	361	6,567
Total reclassified and recognized in net loss, net of tax	(173)	(120)	3,547
Unrealized gain on marketable securities, net of tax	1,864	773	927
Accumulated currency, net of tax	9	(409)	11
Total other comprehensive income, net of tax	1,700	244	4,485
Accumulated other comprehensive income - December 31	$ 6,661	$ 4,961	4,717
Translation loss			9,300
Tax benefit			$ 3,100