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		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net loss—basic and diluted	$ (6,182)	$ (5,307)	$ (10,984)	$ (9,574)
Weighted average common shares outstanding—basic (in shares)	24,155	23,268	23,916	23,078
Dilutive effect of common stock equivalents (in shares)	0	0	0	0
Weighted average common shares outstanding—diluted (in shares)	24,155	23,268	23,916	23,078
Net loss per common share—basic and diluted (in dollars per share)	$ (0.26)	$ (0.23)	$ (0.46)	$ (0.41)