Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2021

Marketable Securities

Schedule of marketable debt securities, classified as available-for-sale

	Gross Unrealized
	Amortized						Fair
	Cost		Gains		Losses		Value
	(In thousands)
September 30, 2021
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	24,291	$	5	$	—	$	24,296
Maturing after one year through three years		75,314		2		(17)		75,299
Total U.S. government and municipal obligations	$	99,605	$	7	$	(17)	$	99,595
Corporate debt securities
Maturing in one year or less	$	183,504	$	—	$	(10)	$	183,494
Maturing after one year through three years		67,844		8		(36)		67,816
Total corporate debt securities	$	251,348	$	8	$	(46)	$	251,310
Total marketable securities	$	350,953	$	15	$	(63)	$	350,905
	Gross Unrealized
	Amortized						Fair
	Cost		Gains		Losses		Value
	(In thousands)
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