Segment Information - Disaggregation information of sales by region (Details) - USD ($)	3 Months Ended								12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Net sales	$ 8,511,000	$ 8,097,000	$ 7,310,000	$ 7,976,000	$ 7,690,000	$ 8,316,000	$ 8,107,000	$ 7,269,000	$ 31,894,262	$ 31,381,521	$ 33,759,953
Domestic United States
Segment Reporting Information [Line Items]
Net sales									23,138,276	23,541,614	25,711,912
Europe
Segment Reporting Information [Line Items]
Net sales									1,422,660	877,308	1,428,245
Canada
Segment Reporting Information [Line Items]
Net sales									829,901	758,145	795,357
Latin America
Segment Reporting Information [Line Items]
Net sales									3,122,929	2,450,969	1,855,013
Middle East
Segment Reporting Information [Line Items]
Net sales									693,716	464,470	857,066
Far East
Segment Reporting Information [Line Items]
Net sales									2,686,206	3,259,905	3,107,339
Other International
Segment Reporting Information [Line Items]
Net sales									$ 574	$ 29,110	$ 5,021