Note 12 - Shareholders' Equity - Stock Option Transactions (Details) - USD ($)	12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Granted, options shares (in shares)	0
Plan 1989 [Member]
Outstanding, options shares (in shares)	229,000	231,000
Outstanding, weighted average exercise price (in dollars per share)	$ 6.05	$ 6.05
Granted, options shares (in shares)	0	0
Exercised, options shares (in shares)	0	0
Forfeited, options shares (in shares)	0	(2,000)
Forfeited, weighted average exercise price (in dollars per share)		$ 6.05
Outstanding, options shares (in shares)	229,000	229,000
Outstanding, weighted average exercise price (in dollars per share)	$ 6.05	$ 6.05
Outstanding, weighted average remaining contractual life (Year)	6 years 11 months 19 days
Outstanding, aggregate intrinsic value	$ 0
Plan 1997 [Member]
Outstanding, options shares (in shares)	2,000	2,000
Outstanding, weighted average exercise price (in dollars per share)	$ 2.74	$ 2.74
Granted, options shares (in shares)	0	0
Exercised, options shares (in shares)	0	0
Forfeited, options shares (in shares)	0	0
Outstanding, options shares (in shares)	2,000	2,000
Outstanding, weighted average exercise price (in dollars per share)	$ 2.74	$ 2.74
Outstanding, weighted average remaining contractual life (Year)	3 years 8 months 19 days
Outstanding, aggregate intrinsic value	$ 0