14. Segment Information (Details) - Schedule of Reconciliation of Depreciation and Amortization from Segment to Consolidated - USD ($) $ in Thousands	12 Months Ended
Apr. 30, 2019	Apr. 30, 2018
Depreciation and amortization (allocated):
Depreciation and Amortization	$ 2,802	$ 2,484
Frequency Electronics Inc New York [Member]
Depreciation and amortization (allocated):
Depreciation and Amortization	2,695	2,355
Frequency Electronics Inc Zyfer [Member]
Depreciation and amortization (allocated):
Depreciation and Amortization	92	114
Corporate Segment [Member]
Depreciation and amortization (allocated):
Depreciation and Amortization	$ 15	$ 15

The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Name:	us-gaap_DepreciationDepletionAndAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration