Earnings Per Common Share - Summary of Reconciliation of Earnings (Loss) Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Basic Earnings (Loss) per Common Share:
Net loss	$ (8,112)	$ (6,218)
Distributed earnings to common shares	0	0
Distributed earnings to participating securities	0	0
Total distributed earnings	0	0
Undistributed loss allocable to common shares	(8,112)	(6,218)
Undistributed earnings allocable to participating securities	0	0
Total undistributed loss	(8,112)	(6,218)
Loss to common shares — basic	$ (8,112)	$ (6,218)
Weighted average common shares outstanding — basic	11,266	10,161
Basic earnings (loss) per common share	$ (0.72)	$ (0.61)
Diluted Earnings (Loss) per Common Share:
Loss to common shares — basic	$ (8,112)	$ (6,218)
Undistributed earnings allocated to participating securities	0	0
Undistributed earnings reallocated to participating securities	0	0
Loss to common shares — diluted	$ (8,112)	$ (6,218)
Weighted average common shares outstanding — basic	11,266	10,161
Dilutive effect of stock options	0	0
Weighted average common shares outstanding — diluted	11,266	10,161
Diluted earnings (loss) per common share	$ (0.72)	$ (0.61)