Note 11 - Shareholders' Equity - Stock Option Transactions (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Plan 1989 [Member]
Outstanding, options shares (in shares)	229,000	229,000
Outstanding, weighted average exercise price (in dollars per share)	$ 6.05	$ 6.05
Granted, options shares (in shares)	125,100	0
Exercised, options shares (in shares)	0	0
Forfeited, options shares (in shares)	(2,000)	0
Granted, weighted average exercise price (in dollars per share)	$ 2.41
Forfeited, weighted average exercise price (in dollars per share)	$ 6.05
Outstanding, options shares (in shares)	352,100	229,000
Outstanding, weighted average exercise price (in dollars per share)	$ 4.76	$ 6.05
Outstanding, weighted average remaining contractual life (Year)	7 years 2 months 23 days
Outstanding, aggregate intrinsic value	$ 0
Outstanding and exercisable, options shares (in shares)	327,100
Outstanding and exercisable, weighted average exercise price (in dollars per share)	$ 4.95
Outstanding and exercisable, weighted average remaining contractual life (Year)	7 years 14 days
Outstanding and exercisable, aggregate intrinsic value	$ 0
Outstanding and non-vested, options shares (in shares)	25,000	0
Outstanding and non-vested, weighted average exercise price (in dollars per share)	$ 2.31
Outstanding and non-vested, weighted average remaining contractual life (Year)	9 years 8 months 4 days
Outstanding and non-vested, aggregate instrinsic value	$ 6,000
Non-vested options (in shares)	0
Non-vested, grant date fair value (in dollars per share)	$ 0
Non-vested, fair value	$ 0
Granted, grant date fair value (in dollars per share)	$ 1.06
Granted, fair value	$ 133,000
Vested options (in shares)	100,100
Vested, grant date fair value (in dollars per share)	$ 1.08
Vested, fair value	$ 108,000
Forfeited non-vested options (in shares)	0
Forfeited, grant date fair value (in dollars per share)	$ 0
Forfeited, fair value	$ 0
Non-vested options (in shares)	25,000	0
Non-vested, grant date fair value (in dollars per share)	$ 0.99	$ 0
Non-vested, fair value	$ 25,000	$ 0
Non-vested, unrecognized compensation expense	$ 9,000
Non-vested, remaining recognition period (Year)	2 months 4 days
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)	2 years 8 months 19 days
Outstanding, aggregate intrinsic value	$ 0
Outstanding and exercisable, options shares (in shares)	2,000
Outstanding and exercisable, weighted average exercise price (in dollars per share)	$ 2.74
Outstanding and exercisable, weighted average remaining contractual life (Year)	2 years 8 months 19 days
Outstanding and exercisable, aggregate intrinsic value	$ 0
Outstanding and non-vested, options shares (in shares)	0
Non-vested options (in shares)	0