Note 12 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Deferred Tax Assets, Net, Total	$ 5,387,000
Deferred Tax Assets, Tax Credit Carryforwards, Research	5,856,000	$ 5,805,000
Deferred Tax Assets, Valuation Allowance, Total	15,012,000	$ 15,017,000
Unrecognized Tax Benefits, Ending Balance	0
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability	2,374,000
State and Local Jurisdiction [Member]
Deferred Tax Assets, Tax Credit Carryforwards, Research	794,000
Internal Revenue Service (IRS) [Member] | Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	44,398,000
Deferred Tax Assets, Tax Credit Carryforwards, Research	$ 2,257,000