Income Taxes - Components of Net Deferred Tax Assets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Deferred tax assets-
Valuation reserves and non-deductible expenses	$ 1,784	$ 1,575
Stock compensation expense not deductible	3,381	3,067
Net operating loss carryforwards	734	765
Tax credit carryforwards	717
Inventory basis differences	1,626	1,376
Other	33
Subtotal	8,275	6,783
Less valuation allowance	(296)	(450)
Deferred tax assets	7,979	6,333
Deferred tax liabilities-
Fixed asset basis differences and depreciation	(862)	(761)
Intangible asset basis differences and amortization	(1,924)	(2,508)
Other	(225)	(306)
Deferred tax liabilities	(3,011)	(3,575)
Net deferred tax assets	$ 4,968	$ 2,758