Shareholders' Equity - Basic and Diluted Earnings Per Common Share Computations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Equity [Abstract]
Net income (loss)	$ 1,070	$ (1,720)	$ (2,841)	$ (4,501)
Weighted average common shares outstanding	57,680	50,597	54,249	50,465
Basic net income (loss) per common share	$ 0.02	$ (0.03)	$ (0.05)	$ (0.09)
Weighted average common shares outstanding	57,680	50,597	54,249	50,465
Diluted net income (loss) per common share	$ 0.02	$ (0.03)	$ (0.05)	$ (0.09)