Segment Information - Disaggregation information of sales by product (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
Respiratory care products
Segment Reporting Information [Line Items]
Net sales									8,555,954	8,993,216	9,037,704
Medical gas equipment
Segment Reporting Information [Line Items]
Net sales									15,282,732	16,031,109	17,645,413
Emergency medical products
Segment Reporting Information [Line Items]
Net sales									$ 8,055,576	$ 6,357,196	$ 7,076,836