We invest in available-for-sale securities consisting of U.S. Treasury securities, money market funds and U.S. Agency bonds. Available-for-sale securities are classified as either cash and cash equivalents or short-term investments on our unaudited condensed balance sheets.

The following tables summarize, by major security type, our short-term investments that are measured at fair value on a recurring basis, in thousands:


		September 30, 2025
	Maturities (years)	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Cash equivalents
Money market funds	1 or less	$	39,180	$	—	$	—		$	39,180
U.S. Treasury securities	1 or less		7,460		—		—			7,460
Total cash equivalents			46,640		—		—			46,640

Short-term investments
U.S. Treasury securities	2 or less		420,960		915		(1	)		421,874
U.S. Agency bonds	3 or less		32,500		9		(5	)		32,504
Total short-term investments			453,460		924		(6	)		454,378
Total		$	500,100	$	924	$	(6	)	$	501,018


		December 31, 2024
	Maturities (years)	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Cash equivalents
Money market funds	1 or less	$	200,024	$	—	$	—		$	200,024

Short-term investments
U.S. Treasury securities	3 or less		497,172		766		—			497,938
U.S. Agency bonds	3 or less		4,997		—		(2	)		4,995
Total short-term investments			502,169		766		(2	)		502,933
Total		$	702,193	$	766	$	(2	)	$	702,957

Short-term investments are classified as current assets, even though the stated maturity date may be one year or more beyond the current balance sheet date, which reflects management’s intention to use the proceeds from sales of these securities to fund our operations, as necessary. As of September 30, 2025 and December 31, 2024, short-term investments of $379.0 million and $393.1 million, respectively, had maturities less than one year, short-term investments of $57.9 million and $97.3 million, respectively, had maturities between one to two years, and short-term investments of $17.5 million and $12.5 million, respectively, had maturities between two to three years. Realized gains and losses were de minimis for the three and nine months ended September 30, 2025 and 2024.

As of September 30, 2025 and December 31, 2024, eight available-for-sale securities with a fair market value of $52.2 million and two available-for-sale securities with a fair market value of $10.0 million, respectively, were in a gross unrealized loss position, none of which were in a continuous unrealized loss position for greater than 12 months. We do not intend to sell such available-for-sale securities, and it is not more likely than not that we will be required to sell such securities prior to recovery of their amortized cost basis. We have no allowance for credit losses as of September 30, 2025 and December 31, 2024. Unrealized gains and losses that are not credit-related are included in accumulated other comprehensive income (loss).

Accrued interest receivable on available-for-sale securities as of September 30, 2025 and December 31, 2024 was $3.3 million in both periods. We have not written off any accrued interest receivables for the nine months ended September 30, 2025 and 2024.