CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (227,413)	$ (209,383)	$ (419,503)
Other comprehensive income (loss):
Net unrealized (loss) gains on marketable securities	(202)	(183)	702
Reclassification adjustments for realization of gain on sale of marketable securities included in net loss	0	(7)	(326)
Foreign currency translation gain (loss)	288	(260)	0
Total other comprehensive income (loss)	86	(450)	376
Comprehensive loss	$ (227,327)	$ (209,833)	$ (419,127)