Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (106,173)	$ (94,664)	$ (309,122)	$ (254,234)
Other comprehensive (loss) income
Unrealized (loss) gain on available-for-sale securities	(26)	279	2,635	(730)
Comprehensive loss	$ (106,199)	$ (94,385)	$ (306,487)	$ (254,964)

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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