LEASES - Components of lease expense (Details) - USD ($)	3 Months Ended	6 Months Ended
	Oct. 31, 2019	Oct. 31, 2019
LEASES
Operating lease expense	$ 126,000	$ 253,000
Amortization of right-to-use assets	13,000	23,000
Interest on lease liabilities	1,000	4,000
Total finance lease expense	14,000	27,000
Total lease expense	$ 140,000	$ 280,000