Marketable Securities

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

4. Marketable Securities

All marketable securities were considered available-for-sale as of September 30, 2023 and December 31, 2022. The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s marketable securities by major security type are summarized in the tables below (in thousands):

	September 30, 2023
	Amortized Cost Basis		Unrealized Gains		Unrealized Losses			Fair Value
Available-for-sale securities
U.S. treasuries	$	4,469	$	—	$	(13	)	$	4,456
Commercial paper		7,942		—		(5	)		7,937
U.S. agency securities		36,700		—		(74	)		36,626
Asset-backed securities		1,982		—		(3	)		1,979
Total available-for-sale securities	$	51,093	$	—	$	(95	)	$	50,998

	December 31, 2022
	Amortized Cost Basis		Unrealized Gains		Unrealized Losses			Fair Value
Available-for-sale securities
U.S. treasuries	$	65,807	$	—	$	(416	)	$	65,391
Commercial paper		115,381		13		(333	)		115,061
U.S. agency securities		53,767		15		(327	)		53,455
Asset-backed securities		1,914		—		—			1,914
Total available-for-sale securities	$	236,869	$	28	$	(1,076	)	$	235,821

The amortized cost of available-for-sale securities is adjusted for amortization of premiums and accretion of discounts to maturity. As of September 30, 2023, the aggregate fair value of securities with remaining maturities of less than one year held by the Company in an unrealized loss position was $51.0 million. The Company has

the intent and ability to hold such securities until recovery and has determined that there has been no material change to its credit risk. As a result, the Company determined it did not hold any investments with a credit loss at September 30, 2023.

There were no realized gains or losses recognized on the sale or maturity of available-for-sale securities during the three and nine months ended September 30, 2023, and as a result, there were no reclassifications out of accumulated other comprehensive gain (loss) for the same periods.

4. Marketable Securities

All marketable securities were considered available-for-sale as of December 31, 2022. The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s marketable securities by major security type are summarized in the table below (in thousands):

	December 31, 2022
	Amortized Cost Basis		Unrealized Gains		Unrealized Losses			Fair Value
Available-for-sale securities
U.S. treasuries	$	65,807	$	—	$	(416	)	$	65,391
Commercial paper		115,381		13		(333	)		115,061
U.S. agency securities		53,767		15		(327	)		53,455
Asset-backed securities		1,914		—		—			1,914
Total available-for-sale securities	$	236,869	$	28	$	(1,076	)	$	235,821

The amortized cost of available-for-sale securities is adjusted for amortization of premiums and accretion of discounts to maturity. As of December 31, 2022, the aggregate fair value of securities with remaining maturities of less than one year held by the Company in an unrealized loss position was $220.5 million. The aggregate fair value of securities with remaining maturities of more than one year held by the Company in an unrealized loss position was $15.3 million. The Company has the intent and ability to hold such securities until recovery and has determined that there has been no material change to its credit risk. As a result, the Company determined it did not hold any investments with a credit loss at December 31, 2022.

There were no realized gains or losses recognized on the sale or maturity of available-for-sale securities during year ended December 31, 2021, and as a result, there were no reclassifications out of accumulated other comprehensive gain (loss) for the same periods.

The Company did not hold any marketable securities as of December 31, 2021.