Stock Options - Activity (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
2012 Employee Stock Option Plan
Options
Outstanding, beginning of year	117,840	72,500	57,200
Granted	0	70,940	29,000
Forfeited/Lapsed	(6,500)	(10,000)
Exercised	(4,300)	(15,600)	(13,700)
Outstanding, end of period	107,040	117,840	72,500
Exercisable, end of period	49,088	35,000	33,800
Weighted average exercise price
Weighted average exercise price, bgn	$ 18.84	$ 11.01	$ 7.09
Granted (per share)		24.50	16.59
Forfeited/Lapsed (per share)	13.82	19.84
Exercised (per share)	18.08	7.55	6.42
Weighted average exercise price, end	19.18	18.84	11.01
Exercisable, end of period, weighted average exercise price	$ 16.14	13.13	8.05
Additional disclosures
Weighted average fair value at grant date of options granted		$ 13.43	$ 9.15
Intrinsic value of options exercised	$ 65,000	$ 278,000	$ 160,000
Intrinsic value of options outstanding	1,840,000	696,000	1,353,000
Intrinsic value of options exercisable	$ 993,000	$ 389,000	$ 731,000
2012 Non-Employee Stock Option Plan
Options
Outstanding, beginning of year	12,000	10,200	27,800
Granted	0	1,800
Forfeited/Lapsed	(4,800)		(1,800)
Exercised	(1,200)	0	(15,800)
Outstanding, end of period	6,000	12,000	10,200
Exercisable, end of period	3,120	5,760	3,000
Weighted average exercise price
Weighted average exercise price, bgn	$ 10.29	$ 7.99	$ 6.85
Granted (per share)		23.35	0
Forfeited/Lapsed (per share)	7.18		8.70
Exercised (per share)	8.70		5.91
Weighted average exercise price, end	13.10	10.29	7.99
Exercisable, end of period, weighted average exercise price	$ 12.08	8.35	$ 6.27
Additional disclosures
Weighted average fair value at grant date of options granted		$ 12.94
Intrinsic value of options exercised	$ 31,000		$ 192,000
Intrinsic value of options outstanding	140,000	$ 157,000	221,000
Intrinsic value of options exercisable	$ 76,000	$ 87,000	$ 70,000
2018 Non-Employee Stock Option Plan
Options
Outstanding, beginning of year	48,400	15,200
Granted	0	33,200	20,000
Forfeited/Lapsed	(11,750)		(3,200)
Exercised	(1,600)	0	(1,600)
Outstanding, end of period	35,050	48,400	15,200
Exercisable, end of period	14,980	12,240	2,400
Weighted average exercise price
Weighted average exercise price, bgn	$ 23.48	$ 16.20
Granted (per share)		26.82	$ 16.20
Forfeited/Lapsed (per share)	23.36		16.20
Exercised (per share)	16.20		16.20
Weighted average exercise price, end	23.85	23.48	16.20
Exercisable, end of period, weighted average exercise price	$ 23.36	21.96	16.20
Additional disclosures
Weighted average fair value at grant date of options granted		$ 15.09	$ 10.24
Intrinsic value of options exercised	$ 29,000		$ 24,000
Intrinsic value of options outstanding	439,000	$ 110,000	205,000
Intrinsic value of options exercisable	$ 195,000	$ 40,000	$ 32,000
2020 Non-Employee Plan
Options
Granted	5,000	0
Exercised	0	0
Outstanding, end of period	5,000
Exercisable, end of period	1,000
Weighted average exercise price
Granted (per share)	$ 22.80
Weighted average exercise price, end	22.80
Exercisable, end of period, weighted average exercise price	22.80
Additional disclosures
Weighted average fair value at grant date of options granted	$ 12.20
Intrinsic value of options outstanding	$ 68,000
Intrinsic value of options exercisable	$ 14,000