Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (37,091)	$ (12,395)	$ 58,975
Other comprehensive income (loss), net of tax:
Foreign currency translation	(6)	(2)	(17)
Total other comprehensive income, net of tax	(6)	(2)	(17)
Comprehensive income (loss)	$ (37,097)	$ (12,397)	$ 58,958