LEASES - Components of lease expense (Details) - USD ($)	3 Months Ended
	Jul. 31, 2020	Jul. 31, 2019
LEASES
Operating lease expense	$ 135,000	$ 112,000
Amortization of right-to-use assets	11,000	10,000
Interest on lease liabilities		3,000
Total finance lease expense	11,000	13,000
Total lease expense	$ 146,000	$ 125,000