Marketable Securities

6 Months Ended

Jun. 30, 2024

Investments, Debt and Equity Securities [Abstract]

3. Marketable Securities

The following tables summarize the fair values of the Company’s marketable securities (in thousands):


	June 30, 2024
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
U.S. treasury securities	$	742,758	$	5	$	(1,156	)	$	741,607
Corporate notes and bonds		452,210		68		(1,317	)		450,961
U.S. agency obligations		346,002		71		(758	)		345,315
Commercial paper		82,010		-		(40	)		81,970
Total marketable securities	$	1,622,980	$	144	$	(3,271	)	$	1,619,853


	December 31, 2023
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
U.S. treasury securities	$	834,235	$	257	$	(1,355	)	$	833,137
U.S. agency obligations		403,035		599		(875	)		402,759
Corporate notes and bonds		279,328		838		(457	)		279,709
Commercial paper		35,407		-		(3	)		35,404
Total marketable securities	$	1,552,005	$	1,694	$	(2,690	)	$	1,551,009

The following tables summarize the fair values and unrealized losses of the Company’s marketable securities, classified by the length of time that the securities have been in a continuous unrealized loss position (in thousands):


	June 30, 2024
	Less than 12 Months					12 Months or Greater					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. treasury securities	$	506,864	$	(788	)	$	181,167	$	(368	)	$	688,031	$	(1,156	)
Corporate notes and bonds		339,304		(1,049	)		50,707		(268	)		390,011		(1,317	)
U.S. agency obligations		209,623		(525	)		95,438		(233	)		305,061		(758	)
Commercial paper		18,055		(40	)		-		-			18,055		(40	)
Total	$	1,073,846	$	(2,402	)	$	327,312	$	(869	)	$	1,401,158	$	(3,271	)


	December 31, 2023
	Less than 12 Months					12 Months or Greater					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. treasury securities	$	487,260	$	(1,074	)	$	46,130	$	(281	)	$	533,390	$	(1,355	)
U.S. agency obligations		206,105		(390	)		80,657		(485	)		286,762		(875	)
Corporate notes and bonds		100,295		(293	)		31,277		(164	)		131,572		(457	)
Commercial paper		6,810		(3	)		-		-			6,810		(3	)
Total	$	800,470	$	(1,760	)	$	158,064	$	(930	)	$	958,534	$	(2,690	)

For available-for-sale debt securities in an unrealized loss position, the Company does not intend to sell these securities and it is more likely than not that the Company will hold these securities until maturity or a recovery of the cost basis. The Company determined that the decline in fair value of these securities was not due to credit-related factors, and no allowance for expected credit losses was recorded as of June 30, 2024 and December 31, 2023. Realized gains and losses were not material for the three and six months ended June 30, 2024 and 2023.

The following table summarizes the contractual maturities of the Company’s marketable securities (in thousands):


	June 30, 2024
	Amortized Cost		Fair Value
Due within one year	$	1,175,453	$	1,173,346
Due after one year through five years		447,527		446,507
Total	$	1,622,980	$	1,619,853