Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (10,226)	$ 1,437	$ (23,966)	$ (3,298)
Other comprehensive income (loss)
Unrealized gain (loss) on marketable securities, net of tax expense of $52 and $0 for the three months ended September 30, 2017 and 2016, respectively, and tax benefit of $8 and $0 for the nine months ended September 30, 2017 and 2016, respectively	(90)	413	13	(21)
Other comprehensive income (loss)	(90)	413	13	(21)
Total comprehensive income (loss)	$ (10,316)	$ 1,850	$ (23,953)	$ (3,319)