Note 2 - Net Income Per Share - Weighted Average Common Shares Outstanding (Details) - USD ($)	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Net income	$ 3,163,439	$ 501,158
Weighted average common shares (in shares)	13,692,533	13,512,094
Dilutive potential common shares (in shares)	4,282	110,132
Weighted average dilutive common shares outstanding (in shares)	13,696,815	13,622,226
Basic (in dollars per share)	$ 0.23	$ 0.04
Diluted (in dollars per share)	$ 0.23	$ 0.04