Note 15 - Share-based Compensation - Stock Options Outstanding (Details)	6 Months Ended
	Mar. 31, 2023 $ / shares shares
Lower Exercise Price (in dollars per share)	$ 1.31
Upper Exercise Price (in dollars per share)	$ 8.03
Number Outstanding (in shares) | shares	4,187,022
Weighted Average Remaining Contractual Life (Year)	4 years 4 months 20 days
Weighted average exercise price, outstanding balance (in dollars per share)	$ 2.94
Number Exercisable (in shares) | shares	1,698,888
Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 2.59
Weighted average exercise price, outstanding balance (in dollars per share)	2.94
Exercisable, Weighted Average Exercise Price (in dollars per share)	2.59
Range One [Member]
Lower Exercise Price (in dollars per share)	1.31
Upper Exercise Price (in dollars per share)	$ 1.99
Number Outstanding (in shares) | shares	1,097,657
Weighted Average Remaining Contractual Life (Year)	11 months 23 days
Weighted average exercise price, outstanding balance (in dollars per share)	$ 1.95
Number Exercisable (in shares) | shares	1,097,657
Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 1.95
Weighted average exercise price, outstanding balance (in dollars per share)	1.95
Exercisable, Weighted Average Exercise Price (in dollars per share)	1.95
Range Two [Member]
Lower Exercise Price (in dollars per share)	2.69
Upper Exercise Price (in dollars per share)	$ 2.69
Number Outstanding (in shares) | shares	1,100,000
Weighted Average Remaining Contractual Life (Year)	6 years 6 months 7 days
Weighted average exercise price, outstanding balance (in dollars per share)	$ 2.69
Number Exercisable (in shares) | shares	0
Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 0
Weighted average exercise price, outstanding balance (in dollars per share)	2.69
Exercisable, Weighted Average Exercise Price (in dollars per share)	0
Range Three [Member]
Lower Exercise Price (in dollars per share)	3.12
Upper Exercise Price (in dollars per share)	$ 3.39
Number Outstanding (in shares) | shares	1,151,138
Weighted Average Remaining Contractual Life (Year)	5 years 2 months 1 day
Weighted average exercise price, outstanding balance (in dollars per share)	$ 3.33
Number Exercisable (in shares) | shares	187,138
Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 3.39
Weighted average exercise price, outstanding balance (in dollars per share)	3.33
Exercisable, Weighted Average Exercise Price (in dollars per share)	3.39
Range Four [Member]
Lower Exercise Price (in dollars per share)	3.40
Upper Exercise Price (in dollars per share)	$ 8.03
Number Outstanding (in shares) | shares	838,227
Weighted Average Remaining Contractual Life (Year)	5 years 3 days
Weighted average exercise price, outstanding balance (in dollars per share)	$ 4.04
Number Exercisable (in shares) | shares	414,093
Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 3.93
Weighted average exercise price, outstanding balance (in dollars per share)	4.04
Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 3.93