Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net loss		$ (3,735)	$ (6,280)	$ (8,429)	$ (13,740)
Other comprehensive income
Unrealized gain on marketable securities, net of tax	[1]	0	194	0	102
Other comprehensive income		0	194	0	102
Total comprehensive loss		$ (3,735)	$ (6,086)	$ (8,429)	$ (13,638)

[1] No tax benefit (expense) for the three and six months ended June 30, 2018. Net of tax benefit of $60 for the three and six months ended June 30, 2017, respectively.