Note 9 - Stock Based Compensation - Summary of Stock Option Activity (Details) - $ / shares	9 Months Ended	12 Months Ended
	Jun. 30, 2023	Sep. 30, 2022
Outstanding (in shares)	55,656
Outstanding, weighted average exercise price (in dollars per share)	$ 151.10
Outstanding, weighted average remaining contractual term (Year)	3 years 10 months 24 days	4 years 6 months 18 days
Granted (in shares)	7,233
Granted, weighted average exercise price (in dollars per share)	$ 11.51
Exercised (in shares)	0
Exercised, weighted average exercise price (in dollars per share)	$ 0
Forfeited (in shares)	(20,678)
Forfeited, weighted average exercise price (in dollars per share)	$ 89.79
Outstanding (in shares)	42,211	55,656
Outstanding, weighted average exercise price (in dollars per share)	$ 143.02	$ 151.10
Exercisable (in shares)	40,402
Exercisable, weighted average exercise price (in dollars per share)	$ 157.02
Exercisable at June 30, 2023 (Year)	4 years 1 month 2 days