Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Consolidated Statements of Comprehensive Loss
Net loss	$ (66,150)	$ (77,187)	$ (38,924)
Other comprehensive loss:
Gain (loss) on translation of foreign operations	266	(44)	(322)
Unrealized (loss) gain on marketable securities	(17)	56	95
Comprehensive loss	$ (65,901)	$ (77,175)	$ (39,151)