Critical Accounting Policies (Revenue Disaggregated By Principal End-User Markets) (Details) - USD ($)	3 Months Ended	6 Months Ended
Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Disaggregation of Revenue [Line Items]
Total Net Sales	$ 69,618,424	$ 74,855,312	$ 130,143,380	$ 148,865,293
Industrial Electronics [Member]
Disaggregation of Revenue [Line Items]
Total Net Sales	35,654,079	41,398,201	72,271,337	84,246,913
Consumer Electronics [Member]
Disaggregation of Revenue [Line Items]
Total Net Sales	30,671,077	28,815,556	51,839,316	55,474,743
Medical / Life Sciences [Member]
Disaggregation of Revenue [Line Items]
Total Net Sales	$ 3,293,268	$ 4,641,555	$ 6,032,727	$ 9,143,637

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration