Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Net loss	$ (168,911)	$ (77,240)
Other comprehensive income (loss):
Unrealized gain (loss) on investments	(40)	844
Amortization of actuarial loss	14	5
Other comprehensive income (loss)	(26)	849
Comprehensive loss	$ (168,937)	$ (76,391)