
	September 30, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Certificates of deposit	$	3,400	$	—	$	(18)	$	3,382
U.S. Treasury securities	5,266		—		(38)		5,228
Commercial paper	2,901		—		(8)		2,893
Corporate notes and bonds	4,131		—		(35)		4,096
Total	$	15,698	$	—	$	(99)	$	15,599


	December 31, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Certificates of deposit	$	1,351	$	—	$	—	$	1,351
U.S. Treasury securities	250		—		—		250
Commercial paper	8,048		—		(2)		8,046
Corporate notes and bonds	13,245		—		(13)		13,232
Total	$	22,894	$	—	$	(15)	$	22,879

The following table summarizes the maturities of the Company’s debt securities available-for-sale investments at September 30, 2022 and December 31, 2021 (in thousands):


	September 30, 2022				December 31, 2021
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in less than 1 year	$	15,698	$	15,599	$	22,663	$	22,649
Due in 1-3 years	—		—		231		230
Total	$	15,698	$	15,599	$	22,894	$	22,879

There were no proceeds from sales of debt securities available-for-sale (including principal paydowns) for the three and nine months ended September 30, 2022 and 2021. The Company determines gains and losses of marketable securities based on specific identification of the securities sold. There were no material realized gains or losses from debt securities available-for-sale for the three and nine months ended September 30, 2022 and 2021. No material balances were reclassified out of accumulated other comprehensive income (loss) for the three and nine months ended September 30, 2022 and 2021. No unrealized losses on debt securities available-for-sale have been recognized in income for the three and nine months ended September 30, 2022 and 2021, as the issuers of such securities held by us were of high credit quality.

As of September 30, 2022, there were no holdings of debt securities available-for-sale of any one issuer, other than the U.S. government, in an amount greater than 10%.

As of September 30, 2022 the Company did not carry any debt securities available-for-sale that were below the Company's minimum credit rating. All debt securities available-for-sale had a credit rating of A- or better as of September 30, 2022.

Equity securities are comprised of investments in mutual funds. The fair value of equity securities for each of the periods ended September 30, 2022 and December 31, 2021 was $0.8 million.

Unrealized losses or gains on equity securities recorded in income during the three and nine months ended September 30, 2022 and 2021 were as follows (in thousands):

These unrealized gains or losses are recorded as a component of other income (expense), net. There were no realized gains or losses from equity securities for each of the three and nine months ended September 30, 2022 and 2021.