Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net loss	$ (27,020)	$ (27,133)	$ (54,732)	$ (65,757)
Change in unrealized gain (loss) on available-for-sale debt securities	(71)	353	(145)	292
Comprehensive loss	$ (27,091)	$ (26,780)	$ (54,877)	$ (65,465)