Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net loss	$ (34,853)	$ (56,153)	$ (75,371)
Other comprehensive income (loss):
Foreign currency translation	(100)	(205)	290
Unrealized loss on marketable securities	(80)	(32)	(45)
Other comprehensive income (loss)	(180)	(237)	245
Comprehensive loss	$ (35,033)	$ (56,390)	$ (75,126)