Note 10 - Warrants - Schedule of Equity-Classified Warrants (Details) - $ / shares	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Outstanding, warrant, contractual term (Year)	2 years 3 months 18 days
Granted, warrants (in shares)	0	293,984
Granted, warrant, weighted average exercise price (in dollars per share)	$ 0	$ 3.75
Exercised, warrants (in shares)	0	(323,444)
Exercised, warrant, weighted average exercise price (in dollars per share)	$ 0	$ 1.25
Forfeited, warrants (in shares)	(70,500)	(224,307)
Forfeited, warrant, weighted average exercise price (in dollars per share)	$ 4.00	$ 5.39
Outstanding, warrants (in shares)	589,917
Outstanding, warrant, weighted average exercise price (in dollars per share)	$ 4.68
Class of warrants, exercisable (in shares)	589,917
Exercisable, weighted average exercise price (in dollars per share)	$ 4.68
Warrants to Purchase Common Stock [Member]
Outstanding, warrants (in shares)	660,417	914,184
Outstanding, warrant, weighted average exercise price (in dollars per share)	$ 4.60	$ 3.88
Outstanding, warrant, contractual term (Year)		3 years 18 days	3 years 2 months 23 days
Outstanding, warrants (in shares)		660,417
Outstanding, warrant, weighted average exercise price (in dollars per share)		$ 4.60
Class of warrants, exercisable (in shares)	589,917
Exercisable, weighted average exercise price (in dollars per share)	$ 4.68