Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended				9 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Income Tax Benefit [Line Items]
Tax (benefit) provision	$ (528,000)			$ 73,000	$ (1,996,000)	$ 657,000
Effective tax rate	75.40%				34.90%
Deferred tax asset valuation allowance	$ 9,300,000				$ 9,300,000		$ 8,200,000
Increase in deferred tax asset valuation allowance		$ 1,100,000
Interest and penalties related to unrecognized tax benefits	0				0	$ 0
Uncertain tax portions	0				0
Cumulative adjustment to retained earnings			$ 1,400,000
Stock Option Exercises [Member]
Income Tax Benefit [Line Items]
Tax (benefit) provision	$ (6,000)				$ (786,000)