Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Net loss	$ (84,609)	$ (48,314)	$ (193,016)	$ (110,912)
Other comprehensive income (loss):
Unrealized gain (loss) on investments	(196)	(159)	99	95
Amortization of actuarial loss	6		17
Other comprehensive income (loss)	(190)	(159)	116	95
Comprehensive loss	$ (84,799)	$ (48,473)	$ (192,900)	$ (110,817)