INCOME TAXES - Statutory Rate Reconciliation (Details) - USD ($)	12 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Income Tax Reconciliation
Computed tax expense at statutory rates	$ 166,000	$ 137,000
Permanent differences	98,000	6,000
State tax and credits	59,000	56,000
Adjustments required by change in method of accounting as a result of adopting ASC 606	(24,000)	31,000
Other	(4,000)
Use of valuation allowance	(220,000)	(217,000)
Total income tax provision (benefit)	$ 75,000	$ 13,000