Condensed Consolidated Statements of Comprehensive Loss - 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	$ (29,764)	$ (29,508)	$ (67,132)	$ (128,860)
Other comprehensive income (loss):
Unrealized gain (loss) on investments	42	(186)	(43)	86
Income (loss) on foreign currency translation adjustments	(1,068)	2,198	(2,439)	1,787
Release of cumulative translation adjustments to loss from discontinued operations	0	0	0	26,957
Comprehensive loss	$ (30,790)	$ (27,496)	$ (69,614)	$ (100,030)