Earnings Per Share - Details of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Numerator:
Net loss	$ (2,381)	$ (2,880)
Dividends paid to preferred stockholders	(141)
Net loss available to common stockholders	$ (2,522)	$ (2,880)
Denominator:
Weighted average shares outstanding – basic	15,299	12,163
Weighted average shares outstanding – diluted	15,299	12,163
Shares excluded due to an exercise price greater than weighted average stock price for the period	1,073	1,908
Net loss per common share:
Basic	$ (0.16)	$ (0.24)
Diluted	$ (0.16)	$ (0.24)