Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (17,167)	$ (8,119)
Other comprehensive income:
Unrealized gain on marketable securities	40	4
Total comprehensive loss	$ (17,127)	$ (8,115)

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

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