CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS
Net loss	$ (26,659)	$ (10,541)	$ (53,400)	$ (31,458)
Unrealized gains (losses) on available-for-sale securities:
Unrealized gains on available-for-sale securities, net of tax	2	(1)	17	35
Comprehensive loss	$ (26,657)	$ (10,542)	$ (53,383)	$ (31,423)