Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Consolidated Statements of Comprehensive Income (Loss)
Net income (loss)	$ (8,953)	$ (23,740)	$ (262,414)	$ (42,918)
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on available-for-sale securities	4	70	4	10
Foreign currency translation	(4)	1	(4)	25
Total other comprehensive income (loss), net of tax		71		35
Total comprehensive income (loss)	$ (8,953)	$ (23,669)	$ (262,414)	$ (42,883)