SEGMENT INFORMATION (Details) - Reconciliation of Operating Profit (Loss) from Segments to Consolidated - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Operating (loss) income:
Operating profit (loss)	$ (939)	$ (1,561)	$ (1,057)	$ (7,263)
Frequency Electronics Inc New York [Member]
Operating (loss) income:
Operating profit (loss)	(413)	(1,493)	(991)	(6,967)
Frequency Electronics Inc Zyfer [Member]
Operating (loss) income:
Operating profit (loss)	(456)	8	211	(36)
Corporate Segment [Member]
Operating (loss) income:
Operating profit (loss)	$ (70)	$ (76)	$ (277)	$ (260)