The Company has certain assets and liabilities that are measured at fair value on a recurring basis according to a fair value hierarchy that prioritizes the inputs, assumptions and valuation techniques used to measure fair value. The three levels of the fair value hierarchy are:

Level 1—Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.

Level 2—Quoted prices in markets that are not active or financial instruments for which all significant inputs are observable, either directly or indirectly.

Level 3—Inputs are generally unobservable and reflect management’s estimates of assumptions that market participants would use in pricing the asset or liability. The fair values are determined using model-based techniques, including probability-based simulation methodologies.

The determination of a financial instrument’s level within the fair value hierarchy is based on an assessment of the lowest level of any input that is significant to the fair value measurement. The Company considers observable data to be market data, which is readily available, regularly distributed or updated, reliable and verifiable, not proprietary, and provided by independent sources that are actively involved in the relevant market.

The following tables reflect the Company’s financial asset balances measured at fair value on a recurring basis (in thousands):


	September 30, 2023
	Level	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Cash equivalents:
Money market fund	2		48		—		—			48
U.S. government debt and agency securities	2		4,968		—		—			4,968
Commercial paper	2		76,625		—		(27	)		76,598
Total cash equivalents		$	81,641	$	—	$	(27	)	$	81,614
Short-term investments:
Commercial paper	2		10,223		—		(11	)		10,212
U.S. government debt and agency securities	2		53,042		—		(640	)		52,402
Total short-term investments		$	63,265	$	—	$	(651	)	$	62,614


	December 31, 2022
	Level	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Cash equivalents:
Money market fund	1	$	7	$	—	$	—		$	7
Commercial paper	2		78,028		—		(26	)		78,002
Total cash equivalents		$	78,035	$	—	$	(26	)	$	78,009
Short-term investments:
Commercial paper	2		36,933		—		(168	)		36,765
U.S. government debt and agency securities	2		65,157		—		(784	)		64,373
Corporate bonds	2		3,302		—		(62	)		3,240
Total short-term investments		$	105,392	$	—	$	(1,014	)	$	104,378
Long-term investments:
U.S. government debt and agency securities	2		45,745		—		(916	)		44,829
Total long-term investments		$	45,745	$	—	$	(916	)	$	44,829

All the commercial paper, U.S. government debt, municipal bonds and agency securities, U.S. treasury bills, and corporate bonds designated as short-term investments have an effective maturity date that is equal to or less than one year from the respective balance sheet date. Those that are designated as long-term investments have an effective maturity date that is more than one year, but less than two years, from the respective balance sheet date.

As of September 30, 2023, the Company does not intend to sell any securities in unrealized loss positions, and it is not more-likely-than-not that the Company will be required to sell such securities prior to the recovery of the amortized cost basis. Based on the Company's assessment, the Company concluded all impairments as of September 30, 2023 to be due to factors other than credit loss, such as changes in interest rates. A credit loss allowance was not recognized and the unrealized losses for available-for-sale securities were recorded in other comprehensive loss.