Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (22,675)	$ (35,339)	$ (53,060)	$ (51,663)
Other comprehensive income:
Cumulative translation (loss) gain	(3)	3		3
Comprehensive loss	$ (22,678)	$ (35,336)	$ (53,060)	$ (51,660)

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

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