CONDENSED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (12,370)	$ (4,003)	$ (23,221)	$ (6,193)
Other comprehensive gain:
Unrealized gain on investment securities	192		228
Comprehensive loss	$ (12,178)	$ (4,003)	$ (22,993)	$ (6,193)

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

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