Marketable Securities (Tables)

12 Months Ended

May 31, 2021

Investments Debt And Equity Securities [Abstract]

Summary of Available-for-Sale Debt Securities by Asset Type

The following tables summarize available-for-sale debt securities held at May 31, 2021 and 2020 by asset type:

	Available-For-Sale Debt Securities
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value (Net Carrying Amount)
May 31, 2021
Fixed maturity:
U.S. treasury and other government	$	26,154	$	593	$	(184	)	$	26,563
Corporate bonds		143		39		-			182
Total available-for-sale debt securities	$	26,297	$	632	$	(184	)	$	26,745

	Available-For-Sale Debt Securities
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value (Net Carrying Amount)
May 31, 2020
Fixed maturity:
U.S. treasury and other government	$	25,462	$	1,314	$	(40	)	$	26,736
Corporate bonds		143		43		-			186
Total available-for-sale debt securities	$	25,605	$	1,357	$	(40	)	$	26,922

Summary of Available-for-Sale Debt Securities in Unrealized Loss Position and Included in Accumulated Other Comprehensive (Loss), Aggregated by Length of Time Investments

Summarized below are the available-for-sale debt securities we held at May 31, 2021 and 2020 that were in an unrealized loss position and that were included in accumulated other comprehensive income (loss), aggregated by the length of time the investments had been in that position:

	May 31, 2021					May 31, 2020
(In thousands)	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Total investments with unrealized losses	$	8,420	$	(184	)	$	2,028	$	(40	)
Unrealized losses with a loss position for less than 12 months		6,920		(152	)		-		-
Unrealized losses with a loss position for more than 12 months		1,500		(32	)		2,028		(40	)

Net Carrying Values of Debt Securities by Contractual Maturity

The net carrying values of available-for-sale debt securities at May 31, 2021, by contractual maturity, are shown below. Expected maturities may differ from contractual maturities because the issuers of the securities may have the right to prepay obligations without prepayment penalties.

(In thousands)	Amortized Cost		Fair Value
Due:
Less than one year	$	3,892	$	3,890
One year through five years		14,591		14,964
Six years through ten years		5,221		5,318
After ten years		2,593		2,573
	$	26,297	$	26,745