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Schedule of Investments and Unrealized Gains/Losses (Details) $ in Thousands	9 Months Ended
	Jan. 31, 2023 USD ($)
Net Investment Income [Line Items]
Amortized Cost	$ 30,005
Unrealized Gains (Losses)	451
Market Value	30,456
Corporate Bonds [Member]
Net Investment Income [Line Items]
Amortized Cost	18,554
Unrealized Gains (Losses)	54
Market Value	18,608
Government Bonds and Notes [Member]
Net Investment Income [Line Items]
Amortized Cost	8,079
Unrealized Gains (Losses)	(22)
Market Value	8,057
Government Agency [Member]
Net Investment Income [Line Items]
Amortized Cost	3,372
Unrealized Gains (Losses)	419
Market Value	$ 3,791

X

- Definition

Cost of the investment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=99383244&loc=d3e12121-115841

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Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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+ References

Reference 1: 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 https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

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