The following table summarizes the available-for-sale securities held at June 30, 2022 (in thousands):


Description	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Commercial paper	$	15,942	$	—	$	(16	)	$	15,926
U.S. government agency securities and U.S. Treasuries		57,653		—		(233	)		57,420
Total	$	73,595	$	—	$	(249	)	$	73,346

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


Description	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Commercial paper	$	68,427	$	7	$	(3	)	$	68,431
U.S. government agency securities and U.S. Treasuries		10,025		—		(1	)		10,024
Total	$	78,452	$	7	$	(4	)	$	78,455

Certain short-term debt securities with original maturities of less than 90 days are included in cash and cash equivalents within the Company's condensed consolidated balance sheets and are not included in the tables above.

The amortized cost of available-for-sale securities is adjusted for amortization of premiums and accretion of discounts to maturity. At June 30, 2022, the balance in the Company’s accumulated other comprehensive loss was composed solely of activity related to the Company’s available-for-sale marketable securities. There were no realized gains or losses recognized on the sale or maturity of available-for-sale securities during the six months ended June 30, 2022, and as a result, the Company did not reclassify any amounts out of accumulated other comprehensive loss for the same period.

The aggregate fair value of available-for-sale securities held by the Company in an unrealized loss position for less than twelve months as of June 30, 2022 was $73.3 million, which consisted of 4 commercial paper securities and 14 United States Treasury securities. The aggregate unrealized loss for those securities in an unrealized loss position for less than twelve months as of June 30, 2022 was less than $0.3 million.

The Company does not intend to sell and it is unlikely that the Company will be required to sell the above investments before recovery of their amortized cost bases, which may be maturity. The Company has determined that there has been no material change in the credit risk of any of its investments. As a result, the Company determined it did not hold any investments that were impaired as of June 30, 2022. The Company reviews its portfolio of available-for-sale debt securities, using both quantitative and qualitative factors, to determine if declines in fair value below cost have resulted from a credit-related loss or other factors. If the decline in fair value is due to credit-related factors, a loss is recognized in net income, whereas if the decline in fair value is not due to credit-related factors, the loss is recorded in other comprehensive income (loss). The weighted-average maturity of the Company’s portfolio was approximately three months at June 30, 2022.