Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net Income (Loss)	$ 12,947	$ (25,155)	$ (84,813)	$ (44,220)
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on short-term investments, net of tax		(6)		15
Comprehensive Net Income (Loss)	$ 12,947	$ (25,161)	$ (84,813)	$ (44,205)