Note 12 - Income Taxes - Deferred Tax Assets (Liabilities) (Details) - USD ($)	Sep. 30, 2017	Sep. 30, 2016
Inventories	$ 291,338	$ 302,600
Bad debts	21,171	3,400
Accrued liabilities	88,817	77,700
Prepaid expense	(73,120)	(8,900)
Depreciation and amortization	220,967	93,000
Research and development and other credit carryforwards	2,179,462	2,019,700
Net operating loss carryforward	520,087	1,303,000
Directors stock option plan	41,537	40,100
Net deferred tax asset	3,290,259	3,830,600
Valuation allowance	(500,000)	(500,000)
Total	$ 2,790,259	$ 3,330,600