CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (13,605)	$ (21,048)	$ (27,906)	$ 12,776
Unrealized (loss) gain on available-for-sale securities, net of tax	0	(1)	0	1
Comprehensive (loss) income	$ (13,605)	$ (21,049)	$ (27,906)	$ 12,777