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
Statement of Comprehensive Income [Abstract]
Net loss	$ (99,923)	$ (92,579)	$ (194,714)	$ (129,082)
Other comprehensive income (loss):
Net unrealized gain on marketable securities, net of tax	17,895	980	8,520	2,021
Comprehensive loss attributable to common stockholders	$ (82,028)	$ (91,599)	$ (186,194)	$ (127,061)