Note 2 - Summary of Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Allowance for doubtful accounts	$ 200,000	$ 200,000	$ 200,000
Additions Charged to Costs and Expenses	8,000	6,000	33,000
Accounts Charged off less Recoveries	(8,000)	(6,000)	(33,000)
Allowance for doubtful accounts	$ 200,000	$ 200,000	$ 200,000