7. FAIR VALUE MEASUREMENTS

Assets and liabilities recorded at fair value in the balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair value. For certain of our financial instruments including amounts receivable and accounts payable the carrying values approximate fair value due to their short-term nature.

ASC 820 “Fair Value Measurements and Disclosures” specifies a hierarchy of valuation techniques based on whether the inputs to those valuation techniques are observable or unobservable. In accordance with ASC 820, these inputs are summarized in the three broad levels listed below:

As quoted prices in active markets are not readily available for certain financial instruments, we obtain estimates for the fair value of financial instruments through third-party pricing service providers.

In determining the appropriate levels, we performed a detailed analysis of the assets and liabilities that are subject to ASC 820.

We invest our excess cash in accordance with investment guidelines that limit the credit exposure to any one financial institution other than securities issued by the U.S. Government. These securities are not collateralized and mature within one year.

A description of the valuation techniques applied to our financial instruments measured at fair value on a recurring basis follows.

Financial Instruments

Money Market Securities

Money market securities are classified within Level 1 of the fair value hierarchy and are valued based on quoted prices in active markets for identical securities.

We only invest in A (or equivalent) rated securities. All securities included in cash and cash equivalents had maturities of 90 days or less at the time of purchase.

Fair Value of Long-Term Debt

Convertible Debt

The principal amount, carrying value and related estimated fair value of our convertible debt reported in the consolidated balance sheets as of December 31, 2023 and December 31, 2022 was as follows (in thousands). The aggregate fair value of the principal amount of the convertible debt is a Level 2 fair value measurement.

Fair Value of Sopharma Share Purchase Agreement Contingent Consideration

We determine the fair value of the contingent consideration using a probability based discounted cash flow model whereby we forecast the timing of the cash flow of the related future payment based on cytisnicline's current clinical development phase and the remaining requirements for regulatory approval. We then discount the expected payment amount to calculate the present value and then apply a probability of success in obtaining regulatory approval as of the valuation date. We evaluate the underlying projection used in determining the fair value each period and make updates as necessary.

The significant assumptions we use to value the contingent consideration are the forecasted timing of the future payment, the risk-adjusted discount rate and the probability of success which are all considered significant unobservable inputs, and as such, the liability is classified as a Level 3 measurement. The risk-adjusted discount rate is adjusted for credit risk.

An increase in the discount rate and decrease in the probability of success will result in a decrease in the fair value of the contingent consideration. Conversely, a decrease in the discount rate and increase in the probability of success will result in an increase in the fair value of the contingent consideration. At December 31, 2023 the risk adjusted discount rate was 38.0% and the probability of success was 67.2%. Adjustments to the fair value of the contingent liabilities, other than payments, are recorded as a gain or loss in the Consolidated Statements of Loss and Comprehensive Loss.