Marketable Securities (Tables)

3 Months Ended

Aug. 31, 2019

Investments Debt And Equity Securities [Abstract]

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

The following tables summarize available-for-sale marketable securities held at August 31, 2019 and May 31, 2019 by asset type:

	Available-For-Sale Securities
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value (Net Carrying Amount)
August 31, 2019
Fixed maturity:
U.S. treasury and other government	$	24,832	$	546	$	(124	)	$	25,254
Corporate bonds		422		57		-			479
Total available-for-sale securities	$	25,254	$	603	$	(124	)	$	25,733

	Available-For-Sale Securities
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value (Net Carrying Amount)
May 31, 2019
Fixed maturity:
U.S. treasury and other government	$	24,483	$	372	$	(308	)	$	24,547
Corporate bonds		422		43		(3	)		462
Total available-for-sale securities	$	24,905	$	415	$	(311	)	$	25,009

Summary of Available-for-Sale 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 securities we held at August 31, 2019 and May 31, 2019 that were in an unrealized loss position and that were included in accumulated other comprehensive (loss), aggregated by the length of time the investments had been in that position:

	August 31, 2019					May 31, 2019
(In thousands)	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Total investments with unrealized losses	$	6,802	$	(124	)	$	11,508	$	(311	)
Unrealized losses with a loss position for less than 12 months		283		-			806		(2	)
Unrealized losses with a loss position for more than 12 months		6,519		(124	)		10,702		(309	)

Net Carrying Values of Debt Securities by Contractual Maturity

The net carrying values of debt securities at August 31, 2019, 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	$	9,370	$	9,338
One year through five years		10,161		10,242
Six years through ten years		4,548		4,816
After ten years		1,175		1,337
	$	25,254	$	25,733