Income Taxes - Deferred Income Tax Assets and Liabilities (Detail) - USD ($)	Sep. 30, 2021	Sep. 30, 2020
Deferred Tax Assets:
Accrued liabilities and reserves	$ 276,000	$ 340,000
Allowance for doubtful accounts	72,000	98,000
Inventory	1,783,000	369,000
Stock-based compensation	79,000	81,000
Net operating losses carryforwards	20,000	5,000
Gross Deferred Income Tax Assets	2,230,000	893,000
Deferred and Other Tax Liabilities:
Domestic international sales corporation	(236,000)	(329,000)
Property and equipment	(1,943,000)	(1,158,000)
Unrealized gain on investment	(295,000)	(2,000)
Unrecognized tax benefits	(150,000)	(150,000)
Gross Deferred and Other Income Tax Liabilities	(2,624,000)	(1,639,000)
Net Deferred and Other Income Tax Assets (Liabilities)	$ (394,000)	$ (746,000)