4. Fair Value Disclosures

Fair value is the price that would be received from the sale of an asset or paid to transfer a liability assuming an orderly transaction to a third party under current market conditions at the measurement date. U.S. GAAP establishes a hierarchical disclosure framework that prioritizes and ranks the level of observability of inputs used in measuring fair value. In connection with historical acquisitions, additional consideration may be paid related to the achievement of certain milestones. The following table provides information for liabilities measured at fair value on a recurring basis using Level 3 inputs:

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The Company initially values contingent consideration related to business combinations using a probability-weighted calculation of potential payment scenarios discounted at rates reflective of the risks associated with the expected future cash flows for certain milestones. Key assumptions used to estimate the fair value of contingent consideration include projected financial information, market data and the probability and timing of achieving the specific targets as discussed in Note 3. Acquisition. After the initial valuation, the Company generally uses its best estimate to measure contingent consideration at each subsequent reporting period using the following unobservable Level 3 inputs:

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Significant changes in these assumptions could result in a significantly higher or lower fair value. The contingent consideration reported in the above table resulted is adjusted quarterly based upon the passage of time or the anticipated success or failure of achieving certain milestones. There was a nominal change in fair value of contingent consideration for the three months ended June 30, 2022 and 2021 of $0.033 million and $0.074 million, respectively. The change in fair value of contingent consideration of $0.267 million for the six months ended June 30, 2022, was primarily driven by changes in estimated probabilities of success related to the orphan drug status designation of the Bayon drug candidate which occurred in March of 2022. The change in fair value of contingent consideration of $(0.496) million for the six months ended June 30, 2021 was primarily driven by changes in the estimated probabilities of success derived from an updated industry study published in the first quarter of 2021. The change in fair value of contingent consideration is recorded within operating expenses on the condensed consolidated statements of operation and comprehensive loss.