Note 2 - Summary of Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($)	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Allowance for doubtful accounts	$ 250,000	$ 250,000
Allowance for doubtful accounts	18,000	(3,000)
Allowance for doubtful accounts	(18,000)	3,000
Allowance for doubtful accounts	250,000	250,000
Allowance for doubtful accounts	$ (18,000)	$ 3,000