Income Taxes - Components of Deferred Income Taxes (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Non-deductible reserves and accruals	$ 9,795	$ 10,164
Net operating loss and other carryforwards	7,862	9,070
Stock compensation	5,900	5,086
Depreciation and amortization	813
Other assets	490	838
Gross deferred tax asset	24,860	25,158
Less - valuation allowance	(1,534)	(1,565)	$ (2,200)	$ (2,086)
Sub-total	23,326	23,593
Depreciation and amortization		(799)
Goodwill amortization	(5,097)	(5,224)
Deferred commissions	(5,344)	(5,399)
Net deferred tax asset	$ 12,885	$ 12,171