Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (11,738)	$ (5,747)	$ (60,461)	$ (43,101)
Other comprehensive gain (loss) (net of tax):
Net change in net unrealized gain (loss) on investments	(130)	8	76	(54)
Net change in unrealized gain (loss) on hedging instruments	224	(152)	486	425
Other comprehensive income (loss)	94	(144)	562	371
Comprehensive loss	$ (11,644)	$ (5,891)	$ (59,899)	$ (42,730)