Stock Options - Stock options outstanding under the 2012 Employee Plan (Details)	6 Months Ended
	Dec. 31, 2019 $ / shares shares
2012 Employee Stock Option Plan [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding, Number outstanding | shares	100,500
Options outstanding, Weighted average remaining contractual life	7 years 9 months 18 days
Options outstanding, Weighted average exercise price	$ 16.34
Options exercisable, Number exercisable | shares	48,400
Options exercisable, Weighted average exercise price	$ 11.10
2012 Employee Stock Option Plan [Member] | Exercise price range $4.37-$33.59 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding, Number outstanding | shares	100,500
Options outstanding, Weighted average remaining contractual life	7 years 9 months 18 days
Options outstanding, Weighted average exercise price	$ 16.34
Options exercisable, Number exercisable | shares	48,400
Options exercisable, Weighted average exercise price	$ 11.10
Exercise price upper limit	33.59
Exercise price lower limit	$ 4.37
2012 Non-Employee Stock Option Plan [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding, Number outstanding | shares	10,200
Options outstanding, Weighted average remaining contractual life	7 years 3 months 18 days
Options outstanding, Weighted average exercise price	$ 7.99
Options exercisable, Number exercisable | shares	5,400
Options exercisable, Weighted average exercise price	$ 7.35
2012 Non-Employee Stock Option Plan [Member] | Exercise price range $4.37 - $8.70 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding, Number outstanding | shares	10,200
Options outstanding, Weighted average remaining contractual life	7 years 3 months 18 days
Options outstanding, Weighted average exercise price	$ 7.99
Options exercisable, Number exercisable | shares	5,400
Options exercisable, Weighted average exercise price	$ 7.35
Exercise price upper limit	8.70
Exercise price lower limit	$ 4.37
2018 Non-Employee Stock Option Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding, Number outstanding | shares	31,200
Options outstanding, Weighted average remaining contractual life	9 years 4 months 24 days
Options outstanding, Weighted average exercise price	$ 23.55
Options exercisable, Number exercisable | shares	8,800
Options exercisable, Weighted average exercise price	$ 21.41
2018 Non-Employee Stock Option Plan | Exercise price range $16.20 - $30.54 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding, Number outstanding | shares	31,200
Options outstanding, Weighted average remaining contractual life	9 years 4 months 24 days
Options outstanding, Weighted average exercise price	$ 23.55
Options exercisable, Number exercisable | shares	8,800
Options exercisable, Weighted average exercise price	$ 21.41
Exercise price upper limit	30.54
Exercise price lower limit	$ 16.20