Note 13 - Stock Repurchase Program (Details Textual) - USD ($)	12 Months Ended			302 Months Ended
	Jun. 30, 2020	Jun. 30, 2019		Jun. 30, 2020	Apr. 30, 1995
Stock Repurchase Program, Authorized Amount	$ 45,500,000			$ 45,500,000	$ 2,000,000
Stock Repurchased and Retired During Period, Shares (in shares)	0	0		43,360,247
Cash Surrender Value of Life Insurance	$ 6,876,827	$ 6,569,628	[1]	$ 6,876,827
Estate of Former Chairman [Member]
Treasury Stock, Repurchase Price, Percentage of Fair Value of Common Stock	95.00%			95.00%
Stock Repurchase Program, Amount to Provide Proceeds Limitation	$ 2,500,000			$ 2,500,000
Percentage of Promissory Note Due To Execute A	25.00%			25.00%
Contingent Promissory Note Term (Year)	4 years
Cash Surrender Value of Life Insurance	$ 1,150,000			$ 1,150,000

[1] Excludes approximately 2,786,225 and 2,523,513 stock options for the years ended June 30, 2020 and 2019, respectively, as the impact of such awards was anti-dilutive.