Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Net income (loss)	$ 4,370	$ (33,063)	$ 43,736
Other comprehensive (loss), before tax:
Foreign currency translation adjustments	(6,444)	(8,592)	(8,178)
Unrealized gains on marketable securities:
Other comprehensive income (loss), before tax	(6,444)	(8,592)	(8,178)
Income tax benefit related to components of other comprehensive loss	(362)	0	0
Other comprehensive (loss), net of tax	(6,806)	(8,592)	(8,178)
Comprehensive income (loss)	$ (2,436)	$ (41,655)	$ 35,558