Subsequent Events	6 Months Ended
Jun. 30, 2025
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent Events On July 1, 2025 (the “Closing Date”), Apellis Pharmaceuticals, Inc. and its subsidiaries Apellis International GmbH and APL DEL Holdings, LLC (collectively, the “Company”) entered into a Royalty Buy-Down Agreement (the “Royalty Agreement”) with Sobi. Under the Royalty Agreement, Sobi agreed to pay the Company an upfront payment of $275.0 million within five business days after the Closing Date, and up to an aggregate of $25.0 million upon the European Medicines Agency ("EMA") approval of Aspaveli for C3G and IC-MPGN (collectively, the "purchase price"), and the Company agreed to reduce Sobi’s royalty payment obligations under the Sobi collaboration agreement (see Note 10), by 90%, effective as of the Closing Date. This royalty reduction is subject to defined caps tied to Aspaveli’s performance, including an initial cap of 1.45x of the purchase price. If a cap is met, Sobi’s royalty payment obligations under the Collaboration Agreement will revert to 100%. The lenders under the Sixth Street Financing Agreement with Sixth Street Lending Partners and the guarantors and lenders party thereto, have consented to the Royalty Agreement, and, in connection with that consent, the Company has agreed to extend by one year from the Closing Date, the periods in which certain prepayment premiums would be owing upon any applicable prepayments of the indebtedness under the Credit Facility provided for under the Sixth Street Financing Agreement.

Subsequent Events

6 Months Ended

Jun. 30, 2025

14. Subsequent Events

On July 1, 2025 (the “Closing Date”), Apellis Pharmaceuticals, Inc. and its subsidiaries Apellis International GmbH and APL DEL Holdings, LLC (collectively, the “Company”) entered into a Royalty Buy-Down Agreement (the “Royalty Agreement”) with Sobi.

Under the Royalty Agreement, Sobi agreed to pay the Company an upfront payment of $275.0 million within five business days after the Closing Date, and up to an aggregate of $25.0 million upon the European Medicines Agency ("EMA") approval of Aspaveli for C3G and IC-MPGN (collectively, the "purchase price"), and the Company agreed to reduce Sobi’s royalty payment obligations under the Sobi collaboration agreement (see Note 10), by 90%, effective as of the Closing Date. This royalty reduction is subject to defined caps tied to Aspaveli’s performance, including an initial cap of 1.45x of the purchase price. If a cap is met, Sobi’s royalty payment obligations under the Collaboration Agreement will revert to 100%.

The lenders under the Sixth Street Financing Agreement with Sixth Street Lending Partners and the guarantors and lenders party thereto, have consented to the Royalty Agreement, and, in connection with that consent, the Company has agreed to extend by one year from the Closing Date, the periods in which certain prepayment premiums would be owing upon any applicable prepayments of the indebtedness under the Credit Facility provided for under the Sixth Street Financing Agreement.