Marketable Securities

12 Months Ended

Dec. 31, 2022

Note 4. Marketable Securities

The following table summarizes the available-for-sale debt securities held at December 31, 2022 and 2021 and (in thousands):


Description	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
December 31, 2022
U.S. treasury securities	$	94,958	$	3	$	(1,111	)	$	93,850
US government agency securities		180,967		25		(1,873	)		179,119
Corporate securities		220,119		25		(2,014	)		218,130
Total	$	496,044	$	53	$	(4,998	)	$	491,099


Description	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
December 31, 2021
U.S. treasury securities	$	186,700	$	—	$	(45	)	$	186,655
US government agency securities		79,657		—		(125	)	$	79,532
Corporate securities		253,929		1		(488	)		253,442
Total	$	520,286	$	1	$	(658	)	$	519,629

As of December 31, 2022, the Company held 149 securities that had been in an unrealized loss position for less than 12 months with an aggregate fair value of $330.9 million. As of December 31, 2021, the Company held 113 securities that had been in an unrealized loss position for less than 12 months with an aggregate fair value of $515.4 million. As of December 31, 2022, the Company held 36 securities that had been in an unrealized loss position for greater than 12 months with an aggregate fair value of $115.0 million. As of December 31, 2021, the Company did not hold any securities that had been in an unrealized loss position for greater than 12 months.

As of December 31, 2022 the Company had 118 securities with a fair value of $338.8 million with a contractual maturity of less than 12 months and 81 securities with a fair value of $152.3 million with a contractual maturity of greater than 12 months. As of December 31, 2021, the Company had 79 securities with a fair value of $394.4 million with a contractual maturity of less than 12 months and 37 securities with a fair value of $125.2 million with a contractual maturity of greater than 12 months.

The Company evaluates securities for other-than-temporary impairments based on quantitative and qualitative factors, and considered the decline in market value for the 185 securities in an unrealized loss position as of December 31, 2022, to be primarily attributable to the then current economic and market conditions. The Company neither intends to sell these investments nor concludes that it is more-likely-than-not that the Company will have to sell them before recovery of their carrying values. The Company also believe that it will be able to collect both principal and interest amounts due at maturity.