Investment valuation | 4. Investment valuation The Company carries its investments at fair value. Fair value is an estimate of the exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants (i.e., the exit price at the measurement date). Fair value measurements are not adjusted for transaction costs. A fair value hierarchy provides for prioritizing inputs to valuation techniques used to measure fair value into three levels: Level 1 Unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 Inputs other than quoted market prices that are observable, either directly or indirectly, and reasonably available. Observable inputs reflect the assumptions market participants would use in pricing the asset or liability and are developed based on market data obtained from sources independent of the Company. Level 3 Unobservable inputs. Unobservable inputs reflect the assumptions that the Company develops based on available information about what market participants would use in valuing the asset or liability. An asset or liability's level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Availability of observable inputs can vary and is affected by a variety of factors. The Company uses judgment in determining fair value of assets and liabilities and Level 3 assets and liabilities involve greater judgment than Level 1 or Level 2 assets or liabilities. As of March 31, 2022 and December 31, 2021, the Company held $5,025,000 and $5,250,000 in U.S. government debt securities. U.S. government securities are valued using a model that incorporates market observable data, such as reported sales of similar securities, broker quotes, yields, bids, offers, and reference data. Certain securities are valued principally using dealer quotations. Money market funds are valued at the closing price reported by the fund sponsor from an actively traded exchange. U.S. government debt securities are categorized in Level 2 of the fair value hierarchy, depending on the inputs used and market activity levels for specific securities. The U.S. government debt securities, which have maturities of three months or less at time of purchase , are reported as Cash and cash equivalents, and those with longer maturities are reported as investments, on the condensed consolidated balance sheets as of March 31, 2022 and December 31, 2021. The following table presents the Company’s financial instruments at fair value (in thousands): Fair Value Measurements as of March 31, 2022 3/31/2022 Quoted Prices Significant Significant Treasury bills included in cash and $ 5,025 $ - $ 5,025 $ - Fair Value Measurements as of December 31, 2021 12/31/2021 Quoted Prices Significant Significant Treasury bills included in cash $ 5,250 $ - $ 5,250 $ - |