Note 9 - Stock Based Compensation - Summary of Stock Option Activity (Details) - $ / shares	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Outstanding (in shares)	2,702,500		1,750,000
Outstanding, weighted average exercise price (in dollars per share)	$ 4.42		$ 4.68
Granted (in shares)	1,060,000	1,380,000
Granted, weighted average exercise price (in dollars per share)	$ 0.97	$ 3.91
Exercised (in shares)	0	(147,953)
Exercised, weighted average exercise price (in dollars per share)	$ 0	$ 2.60
Forfeited (in shares)	(1,260,000)	(279,547)
Forfeited, weighted average exercise price (in dollars per share)	$ 3.63	$ 4.47
Outstanding, weighted average remaining contractual term (Year)	4 years 6 months 18 days		5 years 1 month 17 days
Outstanding (in shares)	2,502,500	2,702,500
Outstanding, weighted average exercise price (in dollars per share)	$ 3.36	$ 4.42
Outstanding, weighted average remaining contractual term (Year)	4 years 6 months 18 days		5 years 1 month 17 days
Exercisable (in shares)	1,549,167
Exercisable, weighted average exercise price (in dollars per share)	$ 4.13
Exercisable at September 30, 2022 (Year)	4 years 8 months 8 days