SEGMENT INFORMATION (Details) - Reconciliation of Operating Profit (Loss) from Segments to Consolidated - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Consolidated operating income (loss)	$ 303	$ 219	$ (1,385)	$ (119)
Frequency Electronics Inc New York [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Consolidated operating income (loss)	(64)	41	(1,075)	(582)
Frequency Electronics Inc Zyfer [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Consolidated operating income (loss)	(132)	306	(99)	667
Inter Segment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Consolidated operating income (loss)	0		(20)
Corporate Segment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Consolidated operating income (loss)	$ 499	$ (128)	$ (191)	$ (204)