Subsequent Event	9 Months Ended
Sep. 30, 2022
Subsequent Events [Abstract]
Subsequent Event	9. Subsequent Event Strategic Financing Agreement On November 4, 2022, the Company entered into a revenue interest financing agreement (“RIFA”) with an affiliate of NovaQuest Capital Management (“NovaQuest”) with respect to royalties from Astellas’s sales of roxadustat in Europe, Japan and the other Astellas territories. Pursuant to the RIFA, NovaQuest agreed to pay FibroGen, within ten business days, an investment amount equal to $50.0 million (the “Investment Amount”), in consideration for certain royalty and other revenue payments FibroGen will make to NovaQuest. FibroGen agreed to pay NovaQuest annually, up to certain caps (see below), 22.5% of all revenue recognized by the Company in respect of net sales of roxadustat in Europe and Japan and the other Astellas territories, and certain other tiered percentages of revenue (in each case paid annually), pursuant to FibroGen’s license and collaboration agreements with Astellas. The RIFA also provides for certain minimum repayment provisions. The total aggregate payments that can be received by NovaQuest under this Agreement are capped at certain fixed multiples of the Investment Amount based upon time. Once NovaQuest receives an aggregate of either $100 million (two times of the Investment Amount) by the end of 2028, $112.5 million (two and a quarter times of the Investment Amount) by the end of 2029, or $125 million (two and a half times of the Investment Amount) by the end of 2030, the Agreement will expire resulting in FibroGen retaining all subsequent Investment roxadustat royalties. FibroGen is also permitted to prepay its obligations according to a prepayment schedule with reduced repayment caps.

Subsequent Event

9 Months Ended

Sep. 30, 2022

9. Subsequent Event

Strategic Financing Agreement

On November 4, 2022, the Company entered into a revenue interest financing agreement (“RIFA”) with an affiliate of NovaQuest Capital Management (“NovaQuest”) with respect to royalties from Astellas’s sales of roxadustat in Europe, Japan and the other Astellas territories. Pursuant to the RIFA, NovaQuest agreed to pay FibroGen, within ten business days, an investment amount equal to $50.0 million (the “Investment Amount”), in consideration for certain royalty and other revenue payments FibroGen will make to NovaQuest. FibroGen agreed to pay NovaQuest annually, up to certain caps (see below), 22.5% of all revenue recognized by the Company in respect of net sales of roxadustat in Europe and Japan and the other Astellas territories, and certain other tiered percentages of revenue (in each case paid annually), pursuant to FibroGen’s license and collaboration agreements with Astellas. The RIFA also provides for certain minimum repayment provisions. The total aggregate payments that can be received by NovaQuest under this Agreement are capped at certain fixed multiples of the Investment Amount based upon time. Once NovaQuest receives an aggregate of either $100 million (two times of the Investment Amount) by the end of 2028, $112.5 million (two and a quarter times of the Investment Amount) by the end of 2029, or $125 million (two and a half times of the Investment Amount) by the end of 2030, the Agreement will expire resulting in FibroGen retaining all subsequent Investment roxadustat royalties. FibroGen is also permitted to prepay its obligations according to a prepayment schedule with reduced repayment caps.