Note 1 - Basis of Presentation and Significant Accounting Policies - Summary of Status of Company's Non-vested Shares (Details)	6 Months Ended
	Mar. 31, 2023 $ / shares shares
Non-vested options (in shares) | shares	931,718
Weighted-Average Grant Date Fair Value, Non-vested Balance (in dollars per share) | $ / shares	$ 1.57
Options, Granted (in shares) | shares	579,350
Weighted-Average Grant Date Fair Value, Non-vested granted (in dollars per share) | $ / shares	$ 0.41
Non-vested options, vested (in shares) | shares	(450,773)
Weighted-Average Grant Date Fair Value, vested (in dollars per share) | $ / shares	$ 1.28
Non-vested options, forfeited (in shares) | shares	(47,954)
Weighted-Average Grant Date Fair Value, forfeited (in dollars per share) | $ / shares	$ 0.81
Non-vested options (in shares) | shares	1,012,341
Weighted-Average Grant Date Fair Value, Non-vested Balance (in dollars per share) | $ / shares	$ 0.94