CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Consolidated Statements of Comprehensive (Loss) Income
Net loss	$ (74,216)	$ (58,020)	$ (17,037)
Other comprehensive income, net of tax
Net change in unrealized gains (losses) on available-for-sale securities	41	(42)
Other comprehensive income (loss), net of tax	41	(42)
Comprehensive loss	$ (74,175)	$ (58,062)	$ (17,037)