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
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS
Net loss	$ (12,894)	$ (11,785)	$ (44,352)	$ (45,070)
Unrealized gains (losses) on available-for-sale securities:
Unrealized gains (losses) on available-for-sale securities, net of tax	(12)	15	23	20
Comprehensive loss	$ (12,906)	$ (11,770)	$ (44,329)	$ (45,050)