CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (4,204)	$ (8,381)	$ (60,539)	$ (18,920)
Other comprehensive income (loss):
Net change in unrealized gain (loss) on available-for-sale marketable securities	(13)	7	(2)	7
Other comprehensive income (loss)	(13)	7	(2)	7
Comprehensive loss	$ (4,217)	$ (8,374)	$ (60,541)	$ (18,913)