Significant Components of Net Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011
Income Taxes [Line Items]
Accruals and reserves not currently deductible	$ 10,489	$ 10,357
Federal, state and foreign tax credits	18,963	22,673
Other assets	1,655	3,304
Net operating loss carryforwards	101,713	119,167
Inventory reserves and valuation	8,790	11,650
Deferred tax assets	141,610	167,151
Depreciation and intangible amortization	5,418	6,851
Deferred tax liabilities	5,418	6,851
Valuation allowance	(16,035)	(162,208)
Net deferred tax asset (liability)	$ 120,157	$ (1,908)