Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (10,890)	$ (6,560)	$ (27,181)	$ (21,796)
Unrealized gain (loss) on available-for-sale securities	48	45	(70)	(18)
Comprehensive loss	$ (10,842)	$ (6,515)	$ (27,251)	$ (21,814)

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

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