Note 2 - Change in Accounting Principle - Cumulative Effect of Changes for Adoption of New Accounting Standard (Details) - USD ($)	3 Months Ended			6 Months Ended
	Dec. 31, 2019	Dec. 31, 2018		Dec. 31, 2019	Dec. 31, 2018		Jun. 30, 2019
Paid in capital							$ 6,333,135
Retained earnings	$ 8,175,480			$ 8,175,480			8,701,942	[1]
Selling, general and administrative expenses	1,586,705	$ 1,559,346	[2]	3,251,305	$ 3,348,935	[2]
Income from operations	(222,618)	103,149	[2]	(539,764)	144,744	[2]
Net (loss) income	$ (215,713)	$ 103,149	[2],[3]	$ (526,462)	$ 144,719	[2],[3],[4]
Basic (in dollars per share)	$ (0.03)	$ 0.01	[2],[3]	$ (0.07)	$ 0.02	[2],[3]
Diluted (in dollars per share)	$ (0.03)	$ 0.01	[2],[3]	$ (0.07)	$ 0.02	[2],[3]
Stock-based compensation expense				$ 284,894	$ 251,169	[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		$ 1,528,374			3,292,122
Income from operations		134,121			201,557
Net (loss) income		$ 134,121			$ 201,532
Basic (in dollars per share)		$ 0.02			$ 0.03
Diluted (in dollars per share)		$ 0.02			$ 0.03
Stock-based compensation expense					$ 194,356
Accounting Standards Update 2016-09 [Member] | Restatement Adjustment [Member]
Paid in capital							146,742
Retained earnings							$ (146,742)
Selling, general and administrative expenses		$ 30,972			56,813
Income from operations		(30,972)			(56,813)
Net (loss) income		$ (30,972)			$ (56,813)
Basic (in dollars per share)		$ (0.01)			$ (0.01)
Diluted (in dollars per share)		$ (0.01)			$ (0.01)
Stock-based compensation expense					$ 56,813

[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)