Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (56,060)	$ (419,503)	$ (123,914)	$ (126,817)
Other comprehensive income:
Net unrealized gains on marketable securities, net of tax	702		3	0
Reclassification adjustments for realization of gain on sale of marketable securities included in net loss, net of tax	(326)		0	0
Total other comprehensive income	$ 376		3	0
Comprehensive loss		$ (419,127)	$ (123,911)	$ (126,817)