The carrying value and amortized cost of the Company’s investments, summarized by major security type, consisted of the following (in thousands):


	December 31, 2024
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
U.S. Treasury notes	$	245,584	$	319	$	—		$	245,903
Government sponsored enterprise securities		190,452		157		(108	)		190,501
	$	436,036	$	476	$	(108	)	$	436,404


	December 31, 2023
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
U.S. Treasury notes	$	75,315	$	47	$	(28	)	$	75,334
Government sponsored enterprise securities		174,867		119		(112	)		174,874
	$	250,182	$	166	$	(140	)	$	250,208

The Company has classified all of its available-for-sale investment securities, including those with maturities beyond one year, as current assets on its consolidated balance sheets based on the highly liquid nature of the investment securities and because these investment securities are considered available for use in current operations. The following table summarizes the contract maturity of the available-for-sale securities we held as of December 31, 2024:

As of December 31, 2023, all of the Company’s available-for-sale investment securities had contractual maturity dates of less than one year. The Company has classified all equity securities as other assets on its consolidated balance sheets.

At December 31, 2024 and 2023, the Company had 17 and 21 securities, respectively, in an unrealized loss position. The following table presents gross unrealized losses and fair value for those available-for-sale investments that were in an unrealized loss position as of December 31, 2024 and December 31, 2023, aggregated by investment category and length of time that individual securities have been in a continuous loss position (in thousands):


	Less Than 12 Months					12 Months or Greater				Total
	Estimated Fair Value		Unrealized Losses			Estimated Fair Value		Unrealized Losses		Estimated Fair Value		Unrealized Losses
December 31, 2024
Government sponsored enterprise securities	$	84,390	$	(108	)	$	—	$	—	$	84,390	$	(108	)
Total	$	84,390	$	(108	)	$	—	$	—	$	84,390	$	(108	)
December 31, 2023
U.S. Treasury notes	$	41,366	$	(28	)	$	—	$	—	$	41,366	$	(28	)
Government sponsored enterprise securities		108,587		(112	)		—		—		108,587		(112	)
Total	$	149,953	$	(140	)	$	—	$	—	$	149,953	$	(140	)

During the first quarter of 2023, the Company made a sale of all of its investments in commercial paper. The proceeds from sales of these securities were $183.0 million and net realized losses from the related sales were $0.5 million. There were no sales of available-for-sale investment securities in 2024.

At each reporting date, the Company performs an evaluation of impairment to determine if any unrealized losses are the result of credit losses. Impairment is assessed at the individual security level. Factors considered in determining whether a loss resulted from a credit loss or other factors include the Company’s intent and ability to hold the investment until the recovery of its amortized cost basis, the extent to which the fair value is less than the amortized cost basis, the length of time and extent to which fair value has been less than the cost basis, the financial condition of the issuer, any historical failure of the issuer to make scheduled interest or principal payments, any changes to the rating of the security by a rating agency, any adverse legal or regulatory events affecting the issuer or issuer’s industry, any significant deterioration in economic conditions.

The Company does not intend to sell the investment in unrealized loss position and it is unlikely that the Company will be required to sell the investment before the recovery of its amortized cost basis. Based on its evaluation, the Company determined its year-to-date credit losses related to its available-for-sale securities were immaterial at December 31, 2024.