Nature of Business and Summary of Significant Accounting Policies - Income Statement location (Details) - USD ($)	12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Research and development	$ 8,024,000	$ 7,620,000	$ 7,257,000
Net sales	143,593,000	114,035,000	101,359,000
Cost of sales	84,437,000	63,287,000	58,515,000
Selling, General and Administrative Expenses [Member]
Advertising and promotion costs	2,889,000	1,306,000	1,722,000
Operating Expenses.
Research and development	8,024,000	7,620,000	7,257,000
Cost of sales [Member] | Shipping and Handling
Cost of sales	1,425,000	1,058,000	1,034,000
Sales revenue, net | Shipping and Handling
Net sales	$ 428,000	$ 395,000	$ 452,000