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	$ (16,461)	$ (14,463)
Other comprehensive gain:
Unrealized holding gains on marketable securities	11	8
Comprehensive loss	$ (16,450)	$ (14,455)

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

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