Cash Equivalents and Marketable Securities

6 Months Ended

Jun. 30, 2024

Investments, Debt and Equity Securities [Abstract]

Cash Equivalents and Marketable Securities

3. Cash Equivalents and Marketable Securities

Cash equivalents and available-for-sale debt securities consisted of the following as of June 30, 2024 and December 31, 2023 (in thousands):

	June 30, 2024
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
Cash equivalents:
Money market funds	$	141,243	$	—	$	—	$	141,243
U.S. treasury securities	20,939		—		(1)		20,938
U.S. government agency securities	23,918		—		(1)		23,917
Corporate debt securities	53,734		—		—		53,734
Total cash equivalents	239,834		—		(2)		239,832
Debt securities:
U.S. treasury securities	307,686		58		(310)		307,434
U.S. government agency securities	291,518		4		(565)		290,957
Corporate debt securities	54,788		6		(116)		54,678
Certificates of deposit	55,779		—		—		55,779
Total debt securities	709,771		68		(991)		708,848
Total cash equivalents and debt securities	$	949,605	$	68	$	(993)	$	948,680

	December 31, 2023
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
Cash equivalents:
Money market funds	$	77,832	$	—	$	—	$	77,832
U.S. treasury securities	239,727		22		—		239,749
U.S. government agency securities	8,388		1		—		8,389
Corporate debt securities	36,905		—		—		36,905
Total cash equivalents	362,852		23		—		362,875
Debt securities:
U.S. treasury securities	264,554		339		(398)		264,495
U.S. government agency securities	366,946		571		(824)		366,693
Corporate debt securities	66,777		72		(109)		66,740
Total debt securities	698,277		982		(1,331)		697,928
Total cash equivalents and debt securities	$	1,061,129	$	1,005	$	(1,331)	$	1,060,803

The following table presents gross unrealized losses and fair values for the securities that were in a continuous unrealized loss position as of June 30, 2024 and December 31, 2023 (in thousands):

	June 30, 2024
	Less than 12 months				Greater than 12 months				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
U.S. treasury securities	$	172,079	$	(233)	$	32,224	$	(77)	$	204,303	$	(310)
U.S. government agency securities	169,415		(276)		109,231		(289)		278,646		(565)
Corporate debt securities	20,129		(56)		13,855		(60)		33,984		(116)
Total	$	361,623	$	(565)	$	155,310	$	(426)	$	516,933	$	(991)

	December 31, 2023
	Less Than 12 Months				12 Months or Greater				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
U.S. treasury securities	$	60,869	$	(159)	$	42,667	$	(239)	$	103,536	$	(398)
U.S. government agency securities	145,594		(364)		80,455		(460)		226,049		(824)
Corporate debt securities	14,749		(59)		12,934		(50)		27,683		(109)
Total	$	221,212	$	(582)	$	136,056	$	(749)	$	357,268	$	(1,331)

The amortized cost and fair value of the available-for-sale debt securities based on contractual maturities are as follows (in thousands):

	June 30, 2024
	Amortized Cost		Fair Value
Due within one year	$	563,277	$	562,488
Due after one year but within five years	146,494		146,360
Total	$	709,771	$	708,848

Accrued interest receivable of $4.3 million and $4.4 million was classified in prepaid expenses and other current assets in the condensed consolidated balance sheet as of June 30, 2024 and December 31, 2023, respectively.

In addition to available-for-sale debt securities, marketable securities also include term bond mutual funds, which are measured at fair value. As of June 30, 2024, we did not have any term bond mutual funds. As of December 31, 2023, the fair value of the term bond mutual funds was $1.6 million. The change in fair value of the term bond mutual funds is recorded in interest and other income, net in the condensed consolidated statements of operations. The realized and unrealized gains recognized in the condensed consolidated statements of operations were not material during the three and six months ended June 30, 2024 and 2023.