Investments

12 Months Ended

Dec. 31, 2023

Investments, Debt and Equity Securities [Abstract]

3. Investments

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


	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


	December 31, 2022
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
U.S. Treasury notes	$	15,956	$	—	$	(11	)	$	15,945
Government sponsored enterprise securities		81,216		16		(291	)		80,941
Municipal bonds		20,873		—		(98	)		20,775
Commercial paper		184,923		30		(637	)		184,316
	$	302,968	$	46	$	(1,037	)	$	301,977

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. As of December 31, 2023 and 2022, all of the Company’s available-for-sale investment securities have 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, 2023 and 2022, the Company had 21 and 43 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, 2023 and December 31, 2022, 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, 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	)
December 31, 2022
U.S. Treasury notes	$	15,945	$	(11	)	$	—	$	—	$	15,945	$	(11	)
Government sponsored enterprise securities		58,254		(291	)		—		—		58,254		(291	)
Municipal bonds		20,775		(98	)		—		—		20,775		(98	)
Commercial paper		135,200		(637	)		—		—		135,200		(637	)
Total	$	230,174	$	(1,037	)	$	—	$	—	$	230,174	$	(1,037	)

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 other sales of available-for-sale investment securities in prior periods.

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, 2023.