In September 2022, we entered into the Purchase Agreement with OrbiMed Royalty & Credit Opportunities IV, LP (“OrbiMed”), an affiliate of OrbiMed Advisors LLC, as collateral agent and administrative agent for the purchasers party thereto (the “Purchasers”). Pursuant to the Purchase Agreement, we received $125.0 million from the Purchasers at closing (the “First Payment”), less certain transaction expenses. We are also entitled to receive up to $125.0 million in subsequent installments as follows: (i) $75.0 million upon our request occurring no later than September 12, 2025 (the “Second Payment”) and (ii) $50.0 million upon our request in connection with certain permitted acquisitions occurring no later than September 12, 2025 (the “Third Payment”), in each case subject to certain funding conditions. To secure our obligations under the Purchase Agreement, we and our subsidiaries have granted OrbiMed a security interest in our core platform technology assets, subject to certain customary exclusions, as defined in the Purchase Agreement.

As consideration for such payments, the Purchasers have a right to receive certain revenue interests (the “Revenue Interests”) from us based on a percentage (the “Applicable Payment Percentage”) of all GAAP revenue (the “Revenue Base”). If only the First Payment has been made, the Applicable Payment Percentage shall be five percent of the quarterly Revenue Base. If both the First Payment and Second Payment have been made, the Applicable Payment Percentage shall be eight percent of the quarterly Revenue Base. If each of the First Payment, Second Payment and Third Payment have been made, the applicable payment percentage applied to the Revenue Interest shall be ten percent of the quarterly Revenue Base.

Payments in respect of the Revenue Interests shall be made quarterly within 45 days following the end of each fiscal quarter (each, a “Revenue Interest Payment”). If OrbiMed has not received Revenue Interest Payments in the aggregate equal to or greater than the sum of its invested capital (the “Cumulative Purchaser Payments”) on or prior to September 12, 2028, the revenue interest rate shall be increased to a rate which, if applied retroactively to our cumulative Revenue Base, would have resulted in Revenue Interest Payments equal to the sum of all Cumulative Purchaser Payments.

OrbiMed will be entitled to 100% of the Revenue Interest Payments until it has received a total cumulative value of 165% of the Cumulative Purchaser Payments (the “Return Cap”), unless full repayment of the amount of the Return Cap has not been made by September 12, 2032, in which case the Return Cap shall be increased to 175% of the Cumulative Purchaser Payments.

Upon the occurrence of a Put Option Event (as defined in the Purchase Agreement), including material divestitures by us, a change in control, material judgments, or bankruptcy events, Purchasers representing at least a majority of the purchase commitments under the Purchase Agreement shall have the right but not the obligation ("the Put Option") to require us to repurchase all of the outstanding Revenue Interests at the applicable price (the “Put/Call Price”). Additionally, at any time following receipt of the First Payment, we may exercise a call option to repurchase all Revenue Interests at the applicable Put/Call Price.

For all Put Option Events other than a change of control or a material divestiture, the Put/Call Price shall be an amount equal to the applicable Return Cap. For a change of control or a material divestiture, prior to March 12, 2024, the Put/Call Price shall be an amount equal to 120% of the Cumulative Purchaser Payments less the sum of all Revenue Interest Payments made by us to the Purchasers prior to such date, between March 12, 2024 and September 12, 2024, the Put/Call Price shall be an amount equal to 125% of the Cumulative Purchaser Payments less the sum of all Revenue Interest Payments made by us to the Purchasers prior to such date, and after September 12, 2024, the Put/Call Price shall be equal to the applicable Return Cap.

We evaluated the terms of the Purchase Agreement and concluded that the features of the Cumulative Purchaser Payments are similar to those of a debt instrument. Accordingly, we accounted for the transaction as debt recorded at amortized cost using the effective interest rate method. We further evaluated the terms of the debt and determined that the Put Option that is exercisable by the Purchasers upon certain contingent events requires bifurcation as a derivative. However, the value of the Put Option was determined to be immaterial due to the remote possibility of exercise. We assess the value of the Put Option periodically.

To determine the amortization of the Purchase Agreement obligation, we are required to estimate the amount and timing of future Revenue Interest Payments based on our estimate of the timing and amount of future revenues and calculate an effective interest rate which will amortize the obligation to zero over the amortization period. The calculated effective interest rate as of December 31, 2023 was 9.2%.

In connection with the Purchase Agreement, we incurred debt issuance costs of $0.6 million. Debt issuance costs have been recorded to debt and are being amortized over the estimated term of the debt using the effective interest method, adjusted on a prospective basis for changes in the underlying assumptions and inputs.

The assumptions used in determining the expected repayment term of the obligation and amortization period of the issuance costs requires that we make estimates that could impact the short- and long-term classification of these costs, as well as the period over which these costs will be amortized. We periodically assess the amount and timing of expected Revenue Interest Payments based on internal forecasts.

To the extent such payments are greater or less than our initial estimates or the timing of such payments is materially different than our original estimates, we will prospectively adjust the amortization of the revenue interest liability and the effective interest rate.

The following table sets forth the revenue interest liability, net activity during the years ended December 31, 2023 and 2022 (in thousands):


Revenue interest liability at inception	$	125,000
Capitalized issuance costs		(625	)
Interest expense		4,238
Revenue interest paid		(493	)
Revenue interest payable		(2,760	)
Revenue interest liability, net at December 31, 2022		125,360
Interest expense		13,800
Revenue interest paid		(6,225	)
Revenue interest payable		(2,275	)
Revenue interest liability, net at December 31, 2023	$	130,660

Revenue interest payable of $2.3 million and $2.8 million was included within the accounts payable balance on the consolidated balance sheet as of December 31, 2023 and 2022, respectively.