Liability Related to Sale of Future Royalties	9 Months Ended
Sep. 30, 2018
Deferred Revenue Disclosure [Abstract]
Liability Related to Sale of Future Royalties	Note 9 - Liability Related to Sale of Future Royalties In February 2017, we entered into a Royalty Purchase Agreement (the “Royalty Agreement”), under which we sold a portion of our right to receive royalties on potential net sales of omecamtiv mecarbil (and potentially other compounds with the same mechanism of action) under the Amgen Agreement to RPI for a payment of $90.0 million (the “Royalty Monetization”). The Royalty Monetization is non-refundable, even if omecamtiv mecarbil is never commercialized. Concurrently, we entered into a Common Stock Purchase Agreement with RPI through which RPI purchased 875,676 shares of our common stock for $10.0 million (the “RPI Common Stock”). We concluded that there are two units of accounting for the Royalty Monetization and the RPI Common Stock: (1) the Liability related to sale of future royalties and (2) the sale of the RPI Common Stock. We determined the fair value for the Liability related to sale of future royalties at the time of the Royalty Monetization to be $96.7 million, with an effective annual non-cash interest rate of 17% based on our estimate of the cash flows to be received over the life of the Royalty Agreement. We further determined that the fair value of the RPI Common Stock was $8.1 million at the time we entered into the Royalty Agreement. We allocated the consideration of $100.0 million and related transaction costs of $1.8 million on a relative fair value basis to the liability for $92.3 million and the common stock for $7.7 million. We continue to accrete the Liability related to sale of future royalties using the interest method with an annual pre-tax interest rate of 17%. The transaction costs are amortized to non-cash interest expense over the estimated term of the Royalty Agreement. As of December 31, 2017, we determined the fair value at $131.6 million, after considering the new statutory effective tax rate of 21% in 2018. We recognized $4.6 million and $3.9 million in non-cash interest expense in the three months ended September 30, 2018 and 2017, respectively, and $13.0 million and $9.9 million in non-cash interest expense in the nine months ended September 30, 2018 and 2017, respectively, related to the Royalty Agreement.

Note 9 - Liability Related to Sale of Future Royalties

In February 2017, we entered into a Royalty Purchase Agreement (the “Royalty Agreement”), under which we sold a portion of our right to receive royalties on potential net sales of omecamtiv mecarbil (and potentially other compounds with the same mechanism of action) under the Amgen Agreement to RPI for a payment of $90.0 million (the “Royalty Monetization”). The Royalty Monetization is non-refundable, even if omecamtiv mecarbil is never commercialized. Concurrently, we entered into a Common Stock Purchase Agreement with RPI through which RPI purchased 875,676 shares of our common stock for $10.0 million (the “RPI Common Stock”).

We concluded that there are two units of accounting for the Royalty Monetization and the RPI Common Stock: (1) the Liability related to sale of future royalties and (2) the sale of the RPI Common Stock. We determined the fair value for the Liability related to sale of future royalties at the time of the Royalty Monetization to be $96.7 million, with an effective annual non-cash interest rate of 17% based on our estimate of the cash flows to be received over the life of the Royalty Agreement. We further determined that the fair value of the RPI Common Stock was $8.1 million at the time we entered into the Royalty Agreement.

We allocated the consideration of $100.0 million and related transaction costs of $1.8 million on a relative fair value basis to the liability for $92.3 million and the common stock for $7.7 million. We continue to accrete the Liability related to sale of future royalties using the interest method with an annual pre-tax interest rate of 17%. The transaction costs are amortized to non-cash interest expense over the estimated term of the Royalty Agreement. As of December 31, 2017, we determined the fair value at $131.6 million, after considering the new statutory effective tax rate of 21% in 2018.

We recognized $4.6 million and $3.9 million in non-cash interest expense in the three months ended September 30, 2018 and 2017, respectively, and $13.0 million and $9.9 million in non-cash interest expense in the nine months ended September 30, 2018 and 2017, respectively, related to the Royalty Agreement.