Note 5 - Stockholders' Equity (Deficit) - Number of Shares Available for Grant (Details) - shares	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Options granted (in shares)	(890,750)	(578,467)
Options forfeited, cancelled, and expired (in shares)	482,593	304,948
Qualified Employee Stock Option Plans [Member]
Shares available for grant (in shares)	1,619,598	911,617
Shareholder approval of Equity Incentive Stock Option Plan (in shares)	1,000,000	1,000,000
Options granted (in shares)	(877,250)	(550,467)
Options forfeited (in shares)		258,448
Remaining 2009 Plan shares cancelled (in shares)	(1,060,524)
Options forfeited, cancelled, and expired (in shares)	479,593
Shares available for grant (in shares)	1,161,417	1,619,598
Director Stock Option Plans [Member]
Shares available for grant (in shares)	74,000	55,500
Shareholder approval of Equity Incentive Stock Option Plan (in shares)	0	0
Options granted (in shares)	(13,500)	(28,000)
Options forfeited (in shares)		46,500
Remaining 2009 Plan shares cancelled (in shares)	0
Options forfeited, cancelled, and expired (in shares)	3,000
Shares available for grant (in shares)	63,500	74,000