Marketable Securities

6 Months Ended

Jun. 30, 2024

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

Note 4. Marketable securities

The following tables summarize the Company’s marketable securities accounted for as available-for-sale securities (in thousands, except years):

	June 30, 2024
	Maturity	Amortized		Unrealized		Unrealized			Estimated
	(in years)	cost		gains		losses			fair value
US treasury securities	1 or less	$	54,294	$	—	$	(75	)	$	54,219
US government agency securities	1 or less		40,655		—		(22	)		40,633
Corporate debt securities	1 or less		39,656		—		(59	)		39,597
Commercial paper	1 or less		101,213		5		(57	)		101,161
US treasury securities	1-2		29,611		15		(7	)		29,619
US government agency securities	1-2		22,213		5		(1	)		22,217
Total		$	287,642	$	25	$	(221	)	$	287,446

	December 31, 2023
	Maturity	Amortized		Unrealized		Unrealized			Estimated
	(in years)	cost		gains		losses			fair value
US treasury securities	1 or less	$	93,377	$	74	$	(148	)	$	93,303
US government agency securities	1 or less		26,783		45		(4	)		26,824
Corporate debt securities	1 or less		10,719		15		—			10,734
Commercial paper	1 or less		88,356		68		(10	)		88,414
US treasury securities	1-2		9,605		37		—			9,642
Total		$	228,840	$	239	$	(162	)	$	228,917

The following tables present fair values and gross unrealized losses for those available-for-sale securities that were in an unrealized loss position as of June 30, 2024 and December 31, 2023, aggregated by category and the length of time that the securities have been in a continuous loss position (in thousands):

	June 30, 2024
	Unrealized losses less than 12 months					Unrealized losses 12 months or greater					Total
	Fair value		Unrealized losses			Fair value		Unrealized losses			Fair value		Unrealized losses
US treasury securities	$	49,730	$	(25	)	$	22,280	$	(57	)	$	72,010	$	(82	)
US government agency securities		45,875		(23	)		—		—			45,875		(23	)
Corporate debt securities		39,597		(59	)		—		—			39,597		(59	)
Commercial paper		73,182		(57	)		—		—			73,182		(57	)
Total	$	208,384	$	(164	)	$	22,280	$	(57	)	$	230,664	$	(221	)

	December 31, 2023
	Unrealized losses less than 12 months					Unrealized losses 12 months or greater				Total
	Fair value		Unrealized losses			Fair value		Unrealized losses		Fair value		Unrealized losses
US treasury securities	$	74,912	$	(148	)	$	—	$	—	$	74,912	$	(148	)
US government agency securities		6,950		(4	)		—		—		6,950		(4	)
Corporate debt securities		748		—			—		—		748		—
Commercial paper		22,944		(10	)		—		—		22,944		(10	)
Total	$	105,554	$	(162	)	$	—	$	—	$	105,554	$	(162	)

As of June 30, 2024, there were 40 available-for-sale securities with an estimated fair value of $230.7 million in gross unrealized loss positions, of which four available-for-sale securities with an estimated fair value of $22.3 million were in an unrealized loss position for more than 12 months. As of December 31, 2023, there were 22 available-for-sale securities with an estimated fair value of $105.6 million in gross unrealized loss positions, none of which were in an unrealized loss position for more than 12 months.

As of June 30, 2024 and December 31, 2023, unrealized losses on available-for-sale securities are not attributed to credit risk. The Company believes that an allowance for credit losses is unnecessary because the unrealized losses on certain of the Company’s available-for-sale securities are due to market factors and changes in interest rates. Additionally, the Company does not intend to sell the securities nor is it more likely than not that the Company will be required to sell the securities before recovery of their amortized cost basis.

Accrued interest on the Company’s available-for-sale securities was $2.2 million and $1.1 million as of June 30, 2024 and December 31, 2023, respectively, and was included in prepaid expenses and other current assets on the condensed consolidated balance sheets.