Warranty Liability (Details) - USD ($)	6 Months Ended	12 Months Ended
	Dec. 31, 2019	Jun. 30, 2019
Warranty reserve:
Beginning warranty reserve	$ 810,000	$ 760,000
Accrual for products sold	28,000	201,000
Expenditures and costs incurred for warranty claims	(68,000)	(151,000)
Ending warranty reserve	$ 770,000	$ 810,000