Net Loss Per Share - Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator:
Net loss available to common stockholders	$ (2,574)	$ (3,280)	$ (4,806)	$ (6,986)
Denominator:
Weighted average shares outstanding - basic	13,179	11,741	12,674	11,632
Potential common shares - options / warrants (treasury stock method)			4
Weighted average shares outstanding - diluted	13,179	11,741	12,678	11,632
Shares excluded due to an exercise price greater than weighted average stock price for the period	1,973	368	1,869	368
Net loss per common share:
Basic	$ (0.20)	$ (0.28)	$ (0.38)	$ (0.60)
Diluted	$ (0.20)	$ (0.28)	$ (0.38)	$ (0.60)