Schedule of Continuous Unrealized Loss Position for 12 Months or Longer (Details) $ in Thousands	Apr. 30, 2022 USD ($)
Unrealized Losses, Securities in a continuous unrealized loss position for 12 months or longer	$ 337
Fair Value, Securities in a continuous unrealized loss position for 12 months or longer	2,600
US Treasury Bill Securities [Member]
Unrealized Losses, Securities in a continuous unrealized loss position for 12 months or longer	80
Fair Value, Securities in a continuous unrealized loss position for 12 months or longer	887
Corporate Bond Securities [Member]
Unrealized Losses, Securities in a continuous unrealized loss position for 12 months or longer	257
Fair Value, Securities in a continuous unrealized loss position for 12 months or longer	$ 1,713

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=124269663&loc=SL82922890-210455

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27337-111563

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 55
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant