Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (10,154)	$ (10,858)
Other comprehensive loss:
Foreign currency translation adjustment	166	(209)
Changes in unrealized gain (loss) on investments, net of income taxes of $0 for the three months ended March 31, 2016 and 2015	334	(26)
Comprehensive loss	$ (9,654)	$ (11,093)