Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2024

Investments, Debt and Equity Securities [Abstract]

The Company’s marketable securities, which consist of highly liquid marketable debt securities, are classified as available-for-sale and are stated at fair value. The following tables summarize the Company’s marketable securities (in thousands):


As of June 30, 2024	Maturity (in years)	Amortized Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value
U.S. Treasury securities	1 or less	$	613,201	$	6	$	(517)	$	612,690

Negotiable certificates of deposit	1 or less	1,959		—		(4)		1,955

U.S. Treasury securities	1 - 2	108,588		62		—		108,650


Total		$	723,748	$	68	$	(521)	$	723,295


As of December 31, 2023	Maturity (in years)	Amortized Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value
U.S. Treasury securities	1 or less	$	301,053	$	102	$	(530)	$	300,625
U.S. Government agency securities	1 or less	5,000		—		(2)		4,998
Negotiable certificates of deposit	1 or less	4,410		1		(4)		4,407

U.S. Treasury securities	1 - 2	98,701		600		(36)		99,265
Negotiable certificates of deposit	1 - 2	980		—		(6)		974
Total		$	410,144	$	703	$	(578)	$	410,269

Schedule of Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value

The following table summarizes marketable securities in a continuous unrealized loss position for which an allowance for credit losses was not recorded (in thousands):


	Less Than 12 Months				12 Months or Greater				Total
As of June 30, 2024	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
U.S. Treasury securities	$	469,288	$	(312)	$	74,471	$	(205)	$	543,759	$	(517)

Negotiable certificates of deposit	734		—		1,221		(4)		1,955		(4)
Total	$	470,022	$	(312)	$	75,692	$	(209)	$	545,714	$	(521)


	Less Than 12 Months				12 Months or Greater				Total
As of December 31, 2023	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
U.S. Treasury securities	$	214,291	$	(566)	$	—	$	—	$	214,291	$	(566)
U.S. Government agency securities	4,998		(2)		—		—		4,998		(2)
Negotiable certificates of deposit	3,665		(10)		—		—		3,665		(10)
Total	$	222,954	$	(578)	$	—	$	—	$	222,954	$	(578)