Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Condensed Consolidated Statements of Comprehensive Loss (Unaudited)
Net loss	$ (19,421)	$ (29,174)	$ (39,501)	$ (43,277)
Other comprehensive loss:
(Loss) gain on translation of foreign operations	(324)	(19)	14	(4)
Gain (loss) on marketable securities	9	41	(1)	70
Comprehensive loss	$ (19,736)	$ (29,152)	$ (39,488)	$ (43,211)