Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement Of Financial Position [Abstract]
Net loss	$ (40,642)	$ (31,403)
Change in unrealized gains and losses on investments	(262)	2,642
Comprehensive loss	$ (40,904)	$ (28,761)