Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net loss	$ (75,985)	$ (53,315)	$ (52,830)
Other comprehensive (loss) income, net of tax
Foreign currency translation adjustment	314	(327)	(2)
Unrealized gain (loss) on available-for-sale securities, net	70	(23)	(62)
Other comprehensive income (loss)	384	(350)	(64)
Comprehensive loss	$ (75,601)	$ (53,665)	$ (52,894)