Marketable Securities (Tables)

9 Months Ended

Sep. 30, 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 September 30, 2021 and December 31, 2020 at net book value:

	September 30, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In thousands)
Marketable securities:
U.S. Treasury and other government securities	$	251,302	$	9	$	(69	)	$	251,242
Financial institution debt securities		395,052		12		(66	)		394,998
Corporate debt securities		32,099		-		(9	)		32,090
Other asset-backed securities		135,702		1		(51	)		135,652
Total	$	814,155	$	22	$	(195	)	$	813,982
	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