The Company follows authoritative accounting guidance, which among other things, defines fair value, establishes a consistent framework for measuring fair value, and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as the exchange price that would be received to sell an asset or paid to transfer a liability (at exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The three levels of inputs that may be used to measure fair value include:

Level 2: Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities in active markets or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3: Unobservable inputs that are supported by little or no market activity.

The following table identifies the Company’s assets and liabilities that were measured at fair value on a recurring basis (in thousands):


June 30, 2022	Level	Amortized Cost		Gross unrealized gains		Gross unrealized losses			Fair Value
Money market funds	1	$	218,690	$	—	$	—		$	218,690
Short-term investments - U.S. Treasury securities	1		40,077		—		(792	)		39,285
Long-term investments - U.S. Treasury securities	1		24,974		—		(756	)		24,218
Total			283,741		—		(1,548	)		282,193
December 31, 2021
Money market funds	1		253,945		—		—			253,945
Long-term investments - U.S. Treasury securities	1		65,106		—		(326	)		64,780
Total	1	$	319,051	$	—	$	(326	)	$	318,725

There were no transfers between the Level 1 and Level 2 categories or into or out of the Level 3 category during the periods presented.

The investments U.S. Treasury securities designated as short-term investments have an effective maturity date equal to or less than one year from the respective balance sheet date. Those 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. The Company evaluated its investments for other-than-temporary impairment and considers the decline in market value for the securities to be primarily attributable to current economic and market conditions. For the investments, it is not more-likely-than-not that the Company will be required to sell the investments, and the Company does not intend to do so prior to the recovery of the amortized cost basis.