Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes Disclosure [Line Items]
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions		$ 642	$ 773	$ 631
Deferred Tax Assets, Valuation Allowance	$ 3,087		7,774	3,087
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount			(4,700)
Unrecognized Tax Benefits	7,684	7,065	8,604	7,684	$ 7,065	$ 7,765
Deferred tax benefits	1,300		1,800	1,300
Federal Net Operating Loss carryforwards			8,300
State Net Operating Loss carryforwards			22,800
Federal alternative minimum tax credit			500
Gross research credits		765	979	722
Deferred Tax Liabilities, Undistributed Foreign Earnings			$ 500
Cumulative changes in ownership percentage			50.00%
Cumulative changes in ownership period			3 years
Realized upon settlement			50.00%
Unrecognized tax benefits that would impact effective tax rate	5,600		$ 6,400	5,600
Accrued interest and penalties associated with uncertain tax positions			200
Interest expense, net of accrued interest reversed		$ (200)	0	$ 100
Income tax reserves and related interest					$ 1,000
Federal research credits [Member]
Income Taxes Disclosure [Line Items]
Federal research credits			$ 3,700
Federal research credits, expiration date			Dec. 31, 2031
Gross State Research Credits [Member]
Income Taxes Disclosure [Line Items]
Gross research credits			$ 8,900
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Amount			8,700
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Amount			$ 200
Federal [Member]
Income Taxes Disclosure [Line Items]
Gross research credits	$ 400