Marketable securities as of September 30, 2026 consisted of the following (in thousands):


			Gross Unrealized
	Amortized Cost		Gains		Losses			Estimated Fair Value
Marketable securities available-for-sale:
U.S. treasury securities	$	455,348	$	—	$	(1,912	)	$	453,436
Corporate debt securities		60,045		—		(147	)		59,898
U.S. government agency securities		80,173		—		(674	)		79,499
Total available-for-sale securities	$	595,566	$	—	$	(2,733	)	$	592,833

Marketable securities as of December 31, 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	$	484,670	$	859	$	—		$	485,529
Corporate debt securities		132,913		44		(16	)		132,941
U.S. government agency securities		81,431		110		(4	)		81,537
Total available-for-sale securities	$	699,014	$	1,013	$	(20	)	$	700,007

As of September 30, 2026, 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 September 30, 2026 (in thousands):

The aggregate fair value of marketable securities with unrealized losses was $592.8 million and $41.3 million as of September 30, 2026 and December 31, 2025, respectively. As of September 30, 2026 and December 31, 2025, ninety-four investments and five investments were in an unrealized loss position, respectively. All such investments have been in an unrealized loss position for less than one 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, U.S. government agency, and corporate debt 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 the three and nine months ended September 30, 2026 and 2025.