Net Loss Per Share - Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Net loss available to common stockholders	$ (1,670)	$ (4,632)	$ (6,501)	$ (11,618)
Denominator:
Weighted average shares outstanding - basic	14,297	12,209	13,221	11,826
Potential common shares - options / warrants (treasury stock method)		2	1	3
Weighted average shares outstanding - diluted	14,297	12,211	13,222	11,829
Shares excluded (anti-dilutive)		2	1	3
Shares excluded due to an exercise price greater than weighted average stock price for the period	1,973	2,062	1,869	2,062
Net loss per common share:
Basic	$ (0.12)	$ (0.38)	$ (0.49)	$ (0.98)
Diluted	$ (0.12)	$ (0.38)	$ (0.49)	$ (0.98)