Income Taxes - Significant Components of Net Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Accruals and reserves not currently deductible	$ 16,448	$ 9,602
Federal, state and foreign tax credits	24,539	22,115
Other assets	4,294	5,939
Net operating loss carryforwards	73,097	63,569
Inventory reserves and valuation	11,342	10,598
Deferred tax assets	129,720	111,823
Depreciation and intangible amortization	25,850	9,388
Deferred tax liabilities	25,850	9,388
Valuation allowance	(104,802)	(18,797)
Net deferred tax liabilities	$ (932)
Net deferred tax asset		$ 83,638