Nature of Business and Summary of Significant Accounting Policies - Income Statement location (Details) - USD ($)	3 Months Ended		9 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Research and development	$ 2,757,000	$ 2,314,000	$ 7,736,000	$ 6,964,000
Net sales	49,267,000	43,532,000	138,490,000	125,339,000
Cost of sales	22,783,000	22,253,000	64,581,000	75,140,000
Selling, General and Administrative Expenses
Advertising and promotion costs	395,000	926,000	1,852,000	2,185,000
Operating Expenses
Research and development	2,757,000	2,314,000	7,736,000	6,964,000
Cost of sales | Shipping and Handling
Cost of sales	421,000	437,000	1,181,000	1,285,000
Sales revenue, net | Shipping and Handling
Net sales	$ 93,000	$ 106,000	$ 279,000	$ 346,000