CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Condensed Consolidated Statements of Comprehensive Loss
Net loss	$ (13,825)	$ (14,169)	$ (38,708)	$ (36,778)
Other comprehensive loss:
Unrealized holding gains (losses) on marketable securities	(4)		(1)
Comprehensive loss	$ (13,829)	$ (14,169)	$ (38,709)	$ (36,778)