Stock Options - Reflects activity (Details) - USD ($)	3 Months Ended		9 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
2012 Employee Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, beginning of year			72,500	57,200
Granted	13,000	0	41,000	24,000
Exercised	(14,100)	(3,700)	(14,100)	(13,200)
Outstanding, end of year	99,400	68,000	99,400	68,000
Exercisable, end of year	36,900	33,000	36,900	33,000
Weighted average fair value at grant date of options granted			$ 15.28	$ 8.76
Total intrinsic value of options exercised			$ 255,000	$ 150,000
Total intrinsic value of options outstanding	$ 241,000	$ 723,000	241,000	723,000
Total intrinsic value of options exercisable	$ 172,000	$ 430,000	$ 172,000	$ 430,000
Outstanding, beginning of year, weighted average exercise price			$ 11.01	$ 7.09
Granted, weighted average exercise price			27.76	15.28
Exercised, weighted average exercise price			7.57	6.43
Outstanding, end of period, weighted average exercise price	$ 18.41	$ 10.11	18.41	10.11
Exercisable, end of period, weighted average exercise price	$ 13.27	$ 7.84	$ 13.27	$ 7.84
2012 Non-Employee Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, beginning of year			10,200	27,800
Granted			1,800
Exercised	0	(3,600)	0	(14,600)
Outstanding, end of year	12,000	13,200	12,000	13,200
Exercisable, end of year	5,760	4,200	5,760	4,200
Weighted average fair value at grant date of options granted			$ 0.00
Total intrinsic value of options exercised				$ 0
Total intrinsic value of options outstanding	$ 73,000	$ 166,000	$ 73,000	166,000
Total intrinsic value of options exercisable	$ 42,000	$ 58,000	$ 42,000	$ 58,000
Outstanding, beginning of year, weighted average exercise price			$ 7.99	$ 6.85
Granted, weighted average exercise price			23.35
Exercised, weighted average exercise price			0.00	5.68
Outstanding, end of period, weighted average exercise price	$ 10.29	$ 8.15	10.29	8.15
Exercisable, end of period, weighted average exercise price	$ 8.35	$ 6.97	$ 8.35	$ 6.97
2018 Non-Employee Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, beginning of year			15,200
Granted	17,200	0	33,200	20,000
Exercised			0	0
Outstanding, end of year	48,400	20,000	48,400	20,000
Exercisable, end of year	12,240	4,000	12,240	4,000
Weighted average fair value at grant date of options granted			$ 15.09	$ 10.24
Total intrinsic value of options outstanding	$ 0	$ 91,000	$ 0	$ 91,000
Total intrinsic value of options exercisable	$ 0	$ 18,000	$ 0	$ 18,000
Outstanding, beginning of year, weighted average exercise price			$ 16.20
Granted, weighted average exercise price			26.82	$ 16.20
Outstanding, end of period, weighted average exercise price	$ 23.48	$ 16.20	23.48	16.20
Exercisable, end of period, weighted average exercise price	$ 21.96	$ 16.20	$ 21.96	$ 16.20