Income Taxes - Components of Deferred Income Tax Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets
Federal benefit of state tax liabilities	$ 7,510	$ 11,420
Reserves, accruals and other	9,251	10,906
Inventory obsolescence	239	14,138
Capitalized research and development	9,941	18,861
Amortization of intangibles other than goodwill	3,903	8,040
Net operating loss carryforwards	63,202	80,808
Depreciation	972	492
Deferred tax assets	95,018	144,665
Deferred Tax Liabilities
Reserves, accruals and other	(1,346)	(287)
Customer relationships	(1,294)	(3,398)
Depreciation	0	0
Deferred tax liability	(2,640)	(3,685)
Less: valuation allowance	(5,368)	(140,915)	$ (154,252)	$ (152,138)
Net deferred tax liabilities	87,010	65
Recorded in the accompanying consolidated balance sheets as
Reserves, accruals and other	$ 87,010	$ 65