Nature of Business and Summary of Significant Accounting Policies - Income Statement location (Details) - USD ($)	3 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Research and development	$ 2,437,000	$ 2,428,000
Net sales	41,676,000	39,493,000
Cost of sales	19,263,000	24,927,000
Selling, General and Administrative Expenses
Advertising and promotion costs	761,000	754,000
Operating Expenses
Research and development	2,437,000	2,428,000
Cost of sales | Shipping and Handling
Cost of sales	371,000	394,000
Sales revenue, net | Shipping and Handling
Net sales	$ 83,000	$ 112,000