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	$ (49,023)	$ (19,699)	$ (85,158)	$ (34,779)
Other comprehensive income (loss):
Unrealized gain on available-for-sale securities	666	307	865	804
Comprehensive loss	$ (48,357)	$ (19,392)	$ (84,293)	$ (33,975)