The carrying amounts of the Company’s accounts receivable, accounts payable, and accrued expenses and other current liabilities, approximate their respective fair values due to their short-term nature. The Company uses a three-tier fair value hierarchy to classify and disclose all assets and liabilities measured at fair value on a recurring basis and to minimize the use of unobservable inputs when determining their fair value. The three tiers are defined as follows:

Level 1—Observable inputs based on unadjusted quoted prices in active markets for identical assets or liabilities

Level 2—Inputs, other than quoted prices in active markets, that are observable either directly or indirectly

Level 3—Unobservable inputs for which there is little or no market data, which require the Company to develop its own assumptions

As of March 31, 2022 and December 31, 2021, the Company held an insignificant amount of cash equivalents which were composed of investments in money market funds. The Company classifies investments in money market funds within Level 1 of the fair value hierarchy as the prices are available from quoted prices in active markets.

In August 2021, the Company entered into an Equity Issuance Agreement with iECURE, Inc. (“iECURE”), pursuant to which iECURE granted the Company partial equity ownership in iECURE (the “iECURE equity”) as partial consideration for a license to use the Company’s PCSK9-directed ARCUS nuclease to insert genes into the PCSK9 locus to develop treatments for four pre-specified rare genetic diseases (the “PCSK9 license”). On issuance, the Company accounted for the iECURE equity at fair value under ASC 825, Financial Instruments (“ASC 825”). Accordingly, the Company adjusts the carrying value of the iECURE equity to fair value each reporting period with any changes in fair value recorded to other income (expense). There was no assessed change in the fair value of the iECURE equity during the three months ended March 31, 2022.

The Company classifies the iECURE equity within Level 3 of the fair value hierarchy as the assessed fair value was based on significant unobservable inputs given iECURE equity is not traded on a public exchange. For additional discussion of accounting for the iECURE Development and License agreement (as defined below) and the iECURE Equity Issuance Agreement (as defined below), refer to Note 9, “Collaboration and License Agreements.”

The following represents assets and liabilities measured at fair value on a recurring basis by the Company (in thousands):

March 31, 2022	Fair Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	12	$	12	$	—	$	—
Investment in iECURE		3,091		—		—		3,091
		3,103		12		—		3,091

December 31, 2021	Fair Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	12	$	12	$	—	$	—
Investment in iECURE		3,091		—	$	—		3,091
	$	3,103	$	12	$	-	$	3,091