Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (80,893)	$ (78,254)	$ (44,348)
Other comprehensive income (loss):
Foreign currency translation adjustment	19
Unrealized (loss) gain on marketable securities	(59)	78	75
Total comprehensive loss	$ (80,933)	$ (78,176)	$ (44,273)