Note 10 - Warrants - Schedule of Equity-Classified Warrants (Details) - $ / shares	9 Months Ended
	Jun. 30, 2023	Oct. 01, 2022
Granted, warrants (in shares)	40,500
Granted, warrant, weighted average exercise price (in dollars per share)	$ 2.52
Exercised, warrants (in shares)	0
Exercised, warrant, weighted average exercise price (in dollars per share)	$ 0
Forfeited, warrants (in shares)	(2,226)
Forfeited, warrant, weighted average exercise price (in dollars per share)	$ 337.50
Class of warrants, exercisable (in shares)	51,478
Exercisable, weighted average exercise price (in dollars per share)	$ 184.50
Warrants to Purchase Common Stock [Member]
Outstanding, warrants (in shares)	13,204
Outstanding, warrant, weighted average exercise price (in dollars per share)	$ 210.45
Outstanding, warrant, contractual term (Year)	2 years 9 months 14 days	2 years 3 months 18 days
Outstanding, warrants (in shares)	51,478
Outstanding, warrant, weighted average exercise price (in dollars per share)	$ 41.37
Class of warrants, exercisable (in shares)	10,978
Exercisable, weighted average exercise price (in dollars per share)	$ 41.37