Note 5 - Revenue Recognition - Disaggregation of Revenue (Details) - USD ($)	3 Months Ended			9 Months Ended
	Mar. 31, 2020	Mar. 31, 2019		Mar. 31, 2020	Mar. 31, 2019
Net Sales	$ 4,789,441	$ 4,860,247	[1]	$ 14,362,862	$ 16,056,313	[1]
UNITED STATES
Net Sales	4,200,797	3,611,654		11,785,603	10,653,071
Non-US [Member]
Net Sales	$ 588,644	$ 1,248,593		$ 2,577,259	$ 5,403,242

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