CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (8,906)	$ (17,534)	$ (18,322)	$ (21,860)
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on investments	1	(47)	1	24
Total other comprehensive income (loss)	1	(47)	1	24
Comprehensive loss	$ (8,905)	$ (17,581)	$ (18,321)	$ (21,836)