Note 14 - Stockholders' Equity - Warrant Activity (Details) - $ / shares	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Outstanding, warrants (in shares)	5,398,907	12,436,427
Outstanding, weighted average exercise price per share (in dollars per share)	$ 3.25	$ 3.25
Outstanding, weighted average remaining contractual period (Year)	1 year 109 days	2 years 109 days	3 years 109 days
Exercised, warrants (in shares)		(38)
Exercised, weighted average exercise price per share (in dollars per share)		$ 3.25
Forfeited or expired, warrants (in shares)		(7,037,482)
Forfeited or expired, weighted average exercise price per share (in dollars per share)		$ 3.25
Outstanding, warrants (in shares)	5,398,907	5,398,907	12,436,427
Outstanding, weighted average exercise price per share (in dollars per share)	$ 3.25	$ 3.25	$ 3.25