CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS [Abstract]
Net loss	$ (25,406)	$ (17,278)	$ (28,569)
Other comprehensive (loss), net of tax:
Change from foreign currency translation, net of tax	0	0	3
Change in unrealized gain (loss) on investments, net of tax	(1)	(1)	4
Total other comprehensive gain (loss), net of tax	(1)	(1)	7
Comprehensive loss	$ (25,407)	$ (17,279)	$ (28,562)