Consolidated Statements Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Consolidated Statements Comprehensive Loss
Net loss	$ (25,870)	$ (27,364)
Other comprehensive (loss) income:
(Loss) gain on short-term investments	(4)	4
Total other comprehensive (loss) income:	(4)	4
Comprehensive loss	$ (25,874)	$ (27,360)