Note 1 - Business Activity and Summary of Significant Accounting Policies (Details Textual) - USD ($)	3 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Jun. 30, 2025
Accounts Receivable, Allowance for Credit Loss	$ 281,000		$ 236,000
Inventory Valuation Reserves	1,413,000		1,413,000
Advertising Expense	3,000	$ 4,000
Impairment of Intangible Assets (Excluding Goodwill)	0	$ 0
Standard Product Warranty Accrual, Current	72,000		35,000
Accrued Expenses [Member]
Standard Product Warranty Accrual, Current	$ 37,000		$ 35,000
Minimum [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	11 years
Product Warranty Obligation, Term (Year)	1 year
Maximum [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	20 years
Product Warranty Obligation, Term (Year)	3 years