Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 39,570	$ (64,649)	$ (208,151)	$ (204,151)
Other comprehensive income (loss):
Unrealized gains (losses) on investments	(1,122)	(132)	(326)	1,763
Reclassification adjustment for net investment (gains) losses included in net loss	0	(11)	372	(11)
Net unrealized gains (losses) on investments	(1,122)	(143)	46	1,752
Currency translation adjustments	58	31	75	(63)
Total other comprehensive income (loss)	(1,064)	(112)	121	1,689
Comprehensive income (loss)	$ 38,506	$ (64,761)	$ (208,030)	$ (202,462)