Note 6 - (Loss) Income Per Common and Common Stock Equivalent Share - Earning Per Share (Details) - USD ($)	3 Months Ended			9 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	[1]	Mar. 31, 2020	Mar. 31, 2019	[1]
Net (loss) income	$ (97,373)	$ 137,880	[2]	$ (623,835)	$ 282,599	[2],[3]
Weighted average shares, basic (in shares)	7,404,831	7,404,831	[2]	7,404,831	7,399,768	[2]
Dilutive effect of stock compensation awards (in shares)		594			8,342
Diluted shares (in shares)	7,404,831	7,405,425	[2]	7,404,831	7,408,110	[2]
Basic (in dollars per share)	$ (0.01)	$ 0.02	[2]	$ (0.08)	$ 0.04	[2]
Diluted (in dollars per share)	$ (0.01)	$ 0.02	[2]	$ (0.08)	$ 0.04	[2]

[1] As adjusted for change in accounting principle (Note 2)

[2] As adjusted for change in accounting principle (Note 2)

[3] As adjusted for change in accounting principle (Note 2)