Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2021

Investments Debt And Equity Securities [Abstract]

Summary of Available-for-sale Marketable Securities

The following table summarizes the Company’s available-for-sale marketable securities as of March 31, 2021 and December 31, 2020 at net book value:

	March 31, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In thousands)
Marketable securities:
U.S. Treasury and other government securities	$	204,473	$	49	$	(4	)	$	204,518
Financial institution debt securities		169,979		7		(45	)		169,941
Corporate debt securities		51,311		1		(13	)		51,299
Other asset-backed securities		33,509		1		(8	)		33,502
Total	$	459,272	$	58	$	(70	)	$	459,260
	December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In thousands)
Marketable securities:
U.S. Treasury and other government securities	$	245,666	$	13	$	(11	)	$	245,668
Financial institution debt securities		138,445		6		(8	)		138,443
Corporate debt securities		41,765		3		(2	)		41,766
Other asset-backed securities		11,474		1		(1	)		11,474
Total	$	437,350	$	23	$	(22	)	$	437,351