Marketable Securities

3 Months Ended

Mar. 31, 2024

Marketable Securities

Marketable Securities

(4)  Marketable Securities

The following is a summary of marketable debt securities, classified as available-for-sale:

	Amortized		Gross Unrealized		Gross Unrealized		Fair
	Cost		Gains		Losses		Value
	(In thousands)
March 31, 2024
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	139,787	$	14	$	(62)	$	139,739
Maturing after one year through three years		93,179		—		(275)		92,904
Total U.S. government and municipal obligations	$	232,966	$	14	$	(337)	$	232,643
Corporate debt securities
Maturing in one year or less	$	371,025	$	141	$	(142)	$	371,024
Maturing after one year through three years		105,130		65		(93)		105,102
Total corporate debt securities	$	476,155	$	206	$	(235)	$	476,126
Total marketable securities	$	709,121	$	220	$	(572)	$	708,769
	Amortized		Gross Unrealized		Gross Unrealized		Fair
	Cost		Gains		Losses		Value
	(In thousands)
December 31, 2023
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	132,459	$	143	$	(53)	$	132,549
Maturing after one year through three years		26,009		77		—		26,086
Total U.S. government and municipal obligations	$	158,468	$	220	$	(53)	$	158,635
Corporate debt securities
Maturing in one year or less	$	183,625	$	300	$	(10)	$	183,915
Maturing after one year through three years		45,977		257		—		46,234
Total corporate debt securities	$	229,602	$	557	$	(10)	$	230,149
Total marketable securities	$	388,070	$	777	$	(63)	$	388,784

The Company holds investment-grade marketable securities. Unrealized losses are generally attributable to changes in interest rates. The aggregate fair value of marketable securities held by the Company in an unrealized loss position as of March 31, 2024 and December 31, 2023 was $458.1 million and $80.4 million, respectively. The Company has the intent and ability to hold its marketable securities until recovery and has determined that there has been no material change to their credit risk. As a result, the Company determined it did not hold any investments with a credit loss at March 31, 2024.

Marketable securities include $4.7 million and $1.9 million in accrued interest at March 31, 2024 and December 31, 2023, respectively.