Loss Per Common Share - Reconciliation of Basic Loss Per Common Share to Diluted Loss Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Net loss—basic and diluted	$ (4,802)	$ (4,266)
Weighted average common shares outstanding—basic (in shares)	23,675	22,887
Dilutive effect of common stock equivalents (in shares)	0	0
Weighted average common shares outstanding—diluted (in shares)	23,675	22,887
Net loss per common share—basic and diluted (in dollars per share)	$ (0.20)	$ (0.19)