Note 2 - Net Income Per Share - Weighted Average Common Shares Outstanding (Details) - USD ($)	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Net income	$ 501,158	$ 1,009,960
Weighted average common shares (in shares)	13,512,094	13,400,383
Dilutive potential common shares (in shares)	110,132
Weighted average dilutive common shares outstanding (in shares)	13,622,226	13,400,383
Basic (in dollars per share)	$ 0.04	$ 0.08
Diluted (in dollars per share)	$ 0.04	$ 0.08