The following tables summarize the Company’s financial assets measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):


		September 30, 2022
	Valuation Hierarchy	Amortized Costs		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Aggregate Fair Value
Assets:
Cash equivalents:
Money market funds	Level 1	$	30,120	$	—	$	—		$	30,120
Short-term investments:
U.S. Treasury securities	Level 1		92,588		2		(607	)		91,983
Corporate debt	Level 2		39,892		—		(329	)		39,563
Commercial paper	Level 2		32,094		—		—			32,094
Total cash equivalents and short-term investments		$	194,694	$	2	$	(936	)	$	193,760


		December 31, 2021
	Valuation Hierarchy	Amortized Costs		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Aggregate Fair Value
Assets:
Cash equivalents:
Money market funds	Level 1	$	60,844	$	—	$	—		$	60,844
Short-term investments:
U.S. Treasury securities	Level 1		18,064		—		(60	)		18,004
Corporate debt	Level 2		124,178		2		(125	)		124,055
Commercial paper	Level 2		15,081		—		—			15,081
Total cash equivalents and short-term investments		$	218,167	$	2	$	(185	)	$	217,984

As of September 30, 2022, the remaining contractual maturities for available-for-sale securities were one month to fourteen months.

Impairment assessments are made at the individual security level at each reporting period. When the fair value of an available-for-sale security is less than its cost at the balance sheet date, a determination is made as to whether the impairment is other-than-temporary and, if it is other-than-temporary, an impairment loss is recognized in earnings equal to the difference between the investment’s amortized cost and fair value at such date. As of September 30, 2022, there were three securities with a total fair value of $16.0 million in an unrealized loss position for more than 12 months. The unrealized losses totaling $0.2 million as of September 30, 2022 were caused by changes in market interest rates or the widening of market spreads subsequent to the initial purchase of these securities, and not related to the underlying credit of the issuers or the underlying collateral. These securities were issued by public reporting companies with an investment-grade rating by at least one bond credit rating agency. As a result, the Company did not consider these investments to be other-than-temporarily impaired as of September 30, 2022. During the three and nine months ended September 30, 2022 and 2021, the Company did not recognize other-than-temporary impairment losses related to its investment securities.