CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (103,916)	$ (55,577)
Other comprehensive gain (loss):
Change in unrealized gain (loss) on available for sale securities, net	260	(4)
Total other comprehensive gain (loss)	260	(4)
Comprehensive loss	$ (103,656)	$ (55,581)