CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (12,924)	$ (14,346)	$ (31,246)	$ (36,206)
Other comprehensive loss, net of tax:
Unrealized loss on investments	(7)	(46)	(6)	(22)
Total other comprehensive loss	(7)	(46)	(6)	(22)
Comprehensive loss	$ (12,931)	$ (14,392)	$ (31,252)	$ (36,228)