Net Loss Per Share - Schedule of Earnings Per Share, Basic and Diluted (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Numerator:
Net loss, as reported	$ (1,199)	$ (1,075)
Less: net loss attributable to participating securities	0	0
Net loss available to common shareholders-basic and diluted	$ (1,199)	$ (1,075)
Weighted-average shares of common stock outstanding	41,846,619	41,469,616
Less: weighted-average shares of unvested restricted common stock outstanding	(1,840,830)	(1,993,177)
Weighted-average number of common shares used in computing basic and diluted net loss per common share	40,005,789	39,476,439
Net loss per share applicable to common shareholders-basic and diluted	$ (0.03)	$ (0.03)