Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (5,607)	$ (8,209)	$ (10,682)	$ (15,542)
Other comprehensive income:
Unrealized gain on investments, net of tax			12	5
Unrealized gain on currency translation	(2)	6	8	4
Other comprehensive income	(2)	6	20	9
Comprehensive loss	$ (5,609)	$ (8,203)	$ (10,662)	$ (15,533)