NOTE J - RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS (Details) - USD ($)	3 Months Ended		6 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017	May 01, 2018
NOTE J - RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS (Details) [Line Items]
Contract with Customer, Liability, Revenue Recognized	$ 11,200,000		$ 20,400,000
Revenues	12,142,000	$ 9,337,000	23,153,000	$ 21,360,000
Accounting Standards Update 2014-09 [Member]
NOTE J - RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS (Details) [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	484,000		484,000
Revenues	$ 1,242,000		$ 2,052,000
Assets [Member] | Accounting Standards Update 2014-09 [Member]
NOTE J - RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS (Details) [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets					$ 87,000
Liabilities, Total [Member] | Accounting Standards Update 2014-09 [Member]
NOTE J - RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS (Details) [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets					109,000
Retained Earnings [Member] | Accounting Standards Update 2014-09 [Member]
NOTE J - RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS (Details) [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets					$ 22,000