Note 3 - Basic and Diluted Net Income Per Share - Basic and Diluted Earnings Per Share (Details) - USD ($)	3 Months Ended						9 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Mar. 31, 2022	Mar. 31, 2021
Net income available to common shareholders	$ 848,013			$ 1,541,724			$ 12,157	$ 5,014,672
Net income available to common shareholders (in shares)	37,844,376			37,474,535			37,574,336	37,432,889
Basic and diluted (in dollars per share)	$ 0.02			$ 0.04			$ 0.00	$ 0.13
Net income available to preferred shareholders	$ 22,121			$ 41,084			$ 319	$ 139,359
Net income available to preferred shareholders (in shares)	987,200			998,624			987,200	1,040,270
Net income available to preferred shareholders (in dollars per share)	$ 0.02			$ 0.04			$ 0.00	$ 0.13
Basic and diluted income per share	$ 870,134			$ 1,582,808			$ 12,476
Basic and diluted income per share (in shares)	38,831,576			38,473,159			38,561,536	38,473,159
Basic and diluted income per share (in dollars per share)	$ 0.02			$ 0.04			$ 0.00	$ 0.13
Basic and diluted income per share	$ 870,134	$ 1,023,335	$ (1,880,993)	$ 1,582,808	$ 1,351,788	$ 2,219,434	$ 12,476	$ 5,154,031