CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (9,665)	$ (8,137)	$ (17,286)
Other comprehensive income (loss):
Unrealized gain (loss) on investments	60	(39)	0
Comprehensive loss	$ (9,605)	$ (8,176)	$ (17,286)