Defined Benefit Pension Plan - Net periodic benefit costs (Details) - USD ($)	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Defined Benefit Pension Plan
Interest cost	$ 398,439	$ 287,227
Expected return on plan assets	(672,908)	(477,617)
Amortization of net actuarial loss	121,990	125,330
Net periodic pension income	$ (152,479)	$ (65,060)