Condensed Consolidated Statements of Comprehensive Loss - 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	$ (84,448)	$ (71,977)	$ (247,721)	$ (139,502)
Other comprehensive income (loss):
Unrealized gains (losses) on investments	(2,806)	751	796	1,895
Reclassification adjustment for net investment (gains) losses included in net loss	(62)	0	372	0
Net unrealized gains (losses) on investments	(2,868)	751	1,168	1,895
Currency translation adjustments	107	(52)	17	(94)
Total other comprehensive income (loss)	(2,761)	699	1,185	1,801
Comprehensive loss	$ (87,209)	$ (71,278)	$ (246,536)	$ (137,701)