Marketable Securities

12 Months Ended

Dec. 31, 2021

Marketable Securities

Marketable Securities

(5) Marketable Securities

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

			Gross		Gross
	Amortized		Unrealized		Unrealized		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
December 31, 2020
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	40,328	$	3	$	(2)	$	40,329
Maturing after one year through three years		—		—		—		—
Total U.S. government and municipal obligations	$	40,328	$	3	$	(2)	$	40,329
Corporate debt securities
Maturing in one year or less	$	110,265	$	2	$	(10)	$	110,257
Maturing after one year through three years		—		—		—		—
Total corporate debt securities	$	110,265	$	2	$	(10)	$	110,257
Total marketable securities	$	150,593	$	5	$	(12)	$	150,586

The Company holds investment grade marketable securities, and none were considered to be other-than-temporarily impaired as of December 31, 2021. Marketable securities include $1.3 million and $0.2 million in accrued interest at December 31, 2021 and December 31, 2020, respectively.