Income Taxes - Significant Components of Net Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Accruals and reserves not currently deductible	$ 11,050	$ 10,489
Federal, state and foreign tax credits	20,084	18,963
Other assets	1,859	1,655
Net operating loss carryforwards	101,717	101,713
Inventory reserves and valuation	9,052	8,790
Deferred tax assets	143,762	141,610
Depreciation and intangible amortization	12,208	5,418
Deferred tax liabilities	12,208	5,418
Valuation allowance	(16,509)	(16,035)
Net deferred tax asset (liability)	$ 115,045	$ 120,157