Derivative Liability

9 Months Ended

Sep. 30, 2021

Derivative Instruments and Hedging Activities Disclosure [Abstract]

DERIVATIVE LIABILITY

Exit Fee

In May 2018, in connection with entering into the Loan Agreement, as defined and discussed in Note 5, we entered into an agreement pursuant to which we agreed to pay $1.5 million in cash (the “Exit Fee”) upon any change of control transaction in respect of the Company or if we obtain both (i) FDA approval of tenapanor for the control of serum phosphorus in adult patients with CKD on dialysis and (ii) FDA approval of tenapanor for the treatment of patients with irritable bowel syndrome with constipation (“IBS-C”), which was obtained on September 12, 2019 when the FDA approved IBSRELA® (tenapanor), a 50 milligram, twice daily oral pill for the treatment of IBS-C in adults (the “Exit Fee Agreement”). Notwithstanding the prepayment or termination of the Term Loan, as defined and discussed in Note 5, our obligation to pay the Exit Fee will expire on May 16, 2028. We concluded that the Exit Fee is a freestanding derivative which should be accounted for at fair value on a

recurring basis. The estimated fair value of the Exit Fee is recorded as a derivative liability and included in accrued expenses and other current liabilities on the accompanying condensed balance sheets.

The fair value of the derivative liability was determined using a discounted cash flow analysis and is classified as a Level 3 measurement within the fair value hierarchy since our valuation utilized significant unobservable inputs. Specifically, the key assumptions included in the calculation of the estimated fair value of the derivative liability include: (i) our estimates of both the probability and timing of a potential $1.5 million payment to Solar Capital Ltd. and Western Alliance Bank as a result of the FDA approvals and (ii) a discount rate which was derived from our estimated cost of debt, adjusted with current LIBOR (or a comparable successor rate if LIBOR no longer exists). Generally, increases or decreases in the probability of occurrence would result in a directionally similar impact in the fair value measurement of the derivative liability and it is estimated that a 10% increase (decrease), not to exceed 100%, in the probability of occurrence would result in a fair value fluctuation of no more than $0.1 million.

Changes in the fair value of recurring measurements included in Level 3 of the fair value hierarchy are presented as other income, net in our statements of operations and were as follows for the nine months ended September 30, 2021 and 2020 (in thousands):


	Nine Months Ended September 30,
	2021		2020
Fair value of Exit Fee derivative liability at January 1	$	1,376	$	969
Change in estimated fair value of Exit Fee derivative liability	(696)		290
Fair value of Exit Fee derivative liability at September 30	$	680	$	1,259

During the nine months ended September 30, 2021 we reduced the value of the derivative liability due the receipt of the CRL from the FDA regarding our NDA for the control of serum phosphorus in adult patients with CKD on dialysis.