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 Comprehensive Income [Abstract]
Net loss	$ (58,004)	$ (60,089)	$ (172,530)	$ (139,213)
Other comprehensive income (loss):
Change in net unrealized gains (losses) related to marketable securities	(15)	(255)	(183)	17
Foreign currency translation adjustments	114	(69)	229	(98)
Total other comprehensive (loss) income	99	(324)	46	(81)
Comprehensive loss	$ (57,905)	$ (60,413)	$ (172,484)	$ (139,294)