CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) [Abstract]
Net loss	$ (4,956)	$ (4,934)	$ (14,694)	$ (18,989)
Other comprehensive gain (loss), net of tax:
Change in unrealized gain (loss) on investments, net of tax	1	(1)	2	(1)
Total other comprehensive income gain (loss), net of tax	1	(1)	2	(1)
Comprehensive loss	$ (4,955)	$ (4,935)	$ (14,692)	$ (18,990)