Nature of Business and Summary of Significant Accounting Policies - Income Statement location (Details) - USD ($)	3 Months Ended		6 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022
Research and development	$ 2,542,000	$ 2,222,000	$ 4,979,000	$ 4,650,000
Net sales	47,547,000	42,314,000	89,223,000	81,807,000
Cost of sales	22,535,000	27,960,000	41,798,000	52,887,000
Selling, General and Administrative Expenses
Advertising and promotion costs	696,000	505,000	1,457,000	1,259,000
Operating Expenses
Research and development	2,542,000	2,222,000	4,979,000	4,650,000
Cost of sales | Shipping and Handling
Cost of sales	389,000	454,000	760,000	848,000
Sales revenue, net | Shipping and Handling
Net sales	$ 103,000	$ 128,000	$ 186,000	$ 240,000