Equity Method Investment	12 Months Ended
Dec. 31, 2021
Equity Method Investments And Joint Ventures [Abstract]
Equity Method Investment	10. Equity Method Investment On April 2, 2021, we entered into a definitive agreement with Sairopa B.V., a private company created by Van Herk Royalty B.V. and D.S. Chahal (the “Sairopa Investors”) to acquire certain non-renal assets of Chinook in exchange for preferred stock in Sairopa. We will hold such shares until such time as there is a liquidation event, as defined in the shareholders agreement, in Sairopa. In accordance with the CVR agreement, 50% of any net proceeds received from this transaction by way of a liquidation event of Sairopa by October 4, 2030, net of deductions permitted under the CVR Agreement, including taxes and certain other expenses, will accrue to the benefit of the CVR holders. As of December 31, 2021, we own a 44% interest in Sairopa. We determined that we have the ability to exercise significant influence over Sairopa but do not have a controlling interest. Therefore, the investment in Sairopa was accounted for using the equity method. Judgment regarding the level of influence over each equity method investment includes considering key factors such as ownership interest, representation on the board of directors, and participation in policy-making decisions. The Sairopa Investors provided an initial capitalization of 12.5 million Euros. We recorded the equity method investment at $10.0 million, which is the fair value of the equity received by us in exchange for the non-renal assets. The sale of the non-renal assets to Sairopa resulted in a $7.2 million gain, which is the difference between the fair value of the equity received and the carrying value of the non-renal assets sold. The gain is reported in our consolidated statement of operations and comprehensive loss during the year ended December 31, 2021. Our equity method investment is reported at cost and adjusted each period for our share of the investee’s income or loss, which is reported in our consolidated statements of operations and comprehensive loss on a one quarter lag. We assess our equity method investment for impairment whenever events or changes in circumstances indicate that the carrying value of the investment may not be recoverable. Refer to Note 2 “Summary of Significant Accounting Policies” for information regarding our Equity Method Investment accounting policies.

Equity Method Investment

12 Months Ended

Dec. 31, 2021

Equity Method Investments And Joint Ventures [Abstract]

10. Equity Method Investment

On April 2, 2021, we entered into a definitive agreement with Sairopa B.V., a private company created by Van Herk Royalty B.V. and D.S. Chahal (the “Sairopa Investors”) to acquire certain non-renal assets of Chinook in exchange for preferred stock in Sairopa. We will hold such shares until such time as there is a liquidation event, as defined in the shareholders agreement, in Sairopa. In accordance with the CVR agreement, 50% of any net proceeds received from this transaction by way of a liquidation event of Sairopa by October 4, 2030, net of deductions permitted under the CVR Agreement, including taxes and certain other expenses, will accrue to the benefit of the CVR holders.

As of December 31, 2021, we own a 44% interest in Sairopa. We determined that we have the ability to exercise significant influence over Sairopa but do not have a controlling interest. Therefore, the investment in Sairopa was accounted for using the equity method. Judgment regarding the level of influence over each equity method investment includes considering key factors such as ownership interest, representation on the board of directors, and participation in policy-making decisions. The Sairopa Investors provided an initial capitalization of 12.5 million Euros. We recorded the equity method investment at $10.0 million, which is the fair value of the equity received by us in exchange for the non-renal assets. The sale of the non-renal assets to Sairopa resulted in a $7.2 million gain, which is the difference between the fair value of the equity received and the carrying value of the non-renal assets sold. The gain is reported in our consolidated statement of operations and comprehensive loss during the year ended December 31, 2021.

Our equity method investment is reported at cost and adjusted each period for our share of the investee’s income or loss, which is reported in our consolidated statements of operations and comprehensive loss on a one quarter lag. We assess our equity method investment for impairment whenever events or changes in circumstances indicate that the carrying value of the investment may not be recoverable. Refer to Note 2 “Summary of Significant Accounting Policies” for information regarding our Equity Method Investment accounting policies.