Marketable Securities

3 Months Ended

Mar. 31, 2022

Marketable Securities

Marketable Securities

(4)  Marketable Securities

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

	Gross Unrealized
	Amortized						Fair
	Cost		Gains		Losses		Value
	(In thousands)
March 31, 2022
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	148,739	$	2	$	(1,194)	$	147,547
Maturing after one year through three years		—		—		—		—
Total U.S. government and municipal obligations	$	148,739	$	2	$	(1,194)	$	147,547
Corporate debt securities
Maturing in one year or less	$	177,807	$	—	$	(602)	$	177,205
Maturing after one year through three years		31,114		—		(691)		30,423
Total corporate debt securities	$	208,921	$	—	$	(1,293)	$	207,628
Total marketable securities	$	357,660	$	2	$	(2,487)	$	355,175
	Gross Unrealized
	Amortized						Fair
	Cost		Gains		Losses		Value
	(In thousands)
December 31, 2021
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	80,674	$	—	$	(133)	$	80,541
Maturing after one year through three years		51,319		—		(184)		51,135
Total U.S. government and municipal obligations	$	131,993	$	—	$	(317)	$	131,676
Corporate debt securities
Maturing in one year or less	$	170,034	$	—	$	(28)	$	170,006
Maturing after one year through three years		67,782		—		(357)		67,425
Total corporate debt securities	$	237,816	$	—	$	(385)	$	237,431
Total marketable securities	$	369,809	$	—	$	(702)	$	369,107

The Company holds investment-grade marketable securities, and none were in a continuous unrealized loss position for more than twelve months as of March 31, 2022 and December 31, 2021. The unrealized losses are attributable to changes in interest rates and the Company does not believe any unrealized losses represent other-than-temporary impairments. Marketable securities include $0.8 million and $1.3 million in accrued interest at March 31, 2022 and December 31, 2021, respectively.