Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement Of Income And Comprehensive Loss [Abstract]
Net loss	$ (43,501)	$ (267,357)	$ (20,174)
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment	(15)	(13)	(75)
Unrealized gain on marketable securities available-for-sale, net of tax expense of ($344)			562
Realized gain on marketable securities available-for-sale, net of tax expense of $344		(565)
Other comprehensive income (loss), net of tax	(15)	(578)	487
Comprehensive loss	$ (43,516)	$ (267,935)	$ (19,687)