Note 2 - Change in Accounting Principle - Cumulative Effect of Changes for Adoption of New Accounting Standard (Details) - USD ($)	3 Months Ended
	Sep. 30, 2019	Sep. 30, 2018		Jun. 30, 2019
Paid in capital				$ 6,333,135
Retained earnings	$ 8,391,193			8,701,942	[1]
Selling, general and administrative expenses	1,664,600	$ 1,789,589	[2]
Income from operations	(317,146)	41,595	[2]
Net (loss) income	$ (310,749)	$ 41,570	[2],[3],[4]
Basic (in dollars per share)	$ (0.04)	$ 0.01	[2],[3]
Diluted (in dollars per share)	$ (0.04)	$ 0.01	[2],[3]
Stock-based compensation expense	$ 148,188	$ 122,642	[4]
Accounting Standards Update 2016-09 [Member] | Previously Reported [Member]
Paid in capital				6,186,393
Retained earnings				8,848,684
Selling, general and administrative expenses		1,763,748
Income from operations		67,436
Net (loss) income		$ 67,411
Basic (in dollars per share)		$ 0.01
Diluted (in dollars per share)		$ 0.01
Stock-based compensation expense		$ 96,801
Accounting Standards Update 2016-09 [Member] | Restatement Adjustment [Member]
Paid in capital				146,742
Retained earnings				$ (146,742)
Selling, general and administrative expenses		25,841
Income from operations		(25,841)
Net (loss) income		$ (25,841)
Basic (in dollars per share)
Diluted (in dollars per share)
Stock-based compensation expense		$ 25,841

[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)

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