Summary of Significant Accounting Policies - Reconciliation of Shares Used to Determine Net Income per Share (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share Disclosure [Line Items]
Net (loss) income	$ (4,039)	$ (3,056)
Weighted average number of shares - basic	42,602,431	42,403,029
Shares underlying options	0	0
Weighted average number of shares outstanding – diluted	42,602,431	42,403,029