Marketable securities as of June 30, 2025 consisted of the following (in thousands):


			Gross Unrealized
	Amortized Cost		Gains		Losses			Estimated Fair Value
Marketable securities available-for-sale:
U.S. treasury securities	$	449,269	$	313	$	(39	)	$	449,543
U.S. government agency securities		73,066		50		(23	)		73,093
Total available-for-sale securities	$	522,335	$	363	$	(62	)	$	522,636

Marketable securities as of December 31, 2024 consisted of the following (in thousands):


			Gross Unrealized
	Amortized Cost		Gains		Losses			Estimated Fair Value
Marketable securities available-for-sale:
U.S. treasury securities	$	189,409	$	288	$	(34	)	$	189,663
U.S. government agency securities		107,722		85		(23	)		107,784
Total available-for-sale securities	$	297,131	$	373	$	(57	)	$	297,447

As of June 30, 2025, all of the Company’s marketable securities are available to the Company for use in current operations. As a result, the Company has classified all of these securities as current assets even though the stated maturity of some individual securities may be one year or more beyond the balance sheet date. The following table shows the fair value of the Company’s marketable securities, by contractual maturity, as of June 30, 2025 (in thousands):

The aggregate fair value of marketable securities with unrealized losses was $193.8 million and $51.0 million as of June 30, 2025 and December 31, 2024, respectively. As of June 30, 2025 and December 31, 2024, twenty-two investments and five investments were in an unrealized loss position, respectively. All such investments have been in an unrealized loss position for less than a year and these losses are considered temporary. The Company has the ability and intent to hold these investments until a recovery of their amortized cost, which may not occur until maturity. The Company expects that U.S. treasury and U.S. government agency securities are subject to minimal credit risk. As a result, the Company did not record any charges for credit-related impairments for its available-for-sale securities for three and six months ended June 30, 2025 and 2024.