Subsequent Event	6 Months Ended
Jun. 30, 2020
Subsequent Events [Abstract]
Subsequent Event	10.Subsequent Event On July 8, 2020, FibroGen Cayman, FibroGen Beijing, and FibroGen International (Hong Kong) Limited (collectively, “FibroGen China”) and AstraZeneca AB (“AstraZeneca”, and together with FibroGen China, the “Parties”) entered into an amendment, effective July 1, 2020, to the China Agreement, relating to the development and commercialization of roxadustat in China (the “Amendment”). The Amendment provides for the establishment of a jointly owned entity (the “Distribution Entity”) that will perform roxadustat distribution, as well as conduct sales and marketing through AstraZeneca. FibroGen Beijing will continue to hold all of the regulatory licenses issued by China regulatory authorities and will continue to be primarily responsible for regulatory, clinical, manufacturing, medical affairs and pharmacovigilance. In July 2020, the Company closed the acquisition of an entity for the purpose of the establishment of the Distribution Entity. While the responsibilities of the Parties under the China Agreement remain largely the same, certain changes were made. The Parties have changed the method under which commercial expenses incurred by AstraZeneca are billed, and the collaboration has been adjusted to more fully account for the cost of manufacturing incurred by FibroGen Beijing. The Company is in the process of evaluating the accounting impacts resulting from the Amendment and the establishment of the Distribution Entity, which is expected to be significant to its consolidated financial statements starting the third quarter of 2020. Among others, the accrued long-term co-promotional expenses related to the estimated amount payable to AstraZeneca for its sales and marketing efforts associated with the commercial launch and sales for roxadustat will be reduced by approximately $82 million in the third quarter of 2020.

Subsequent Event

6 Months Ended

Jun. 30, 2020

10.Subsequent Event

On July 8, 2020, FibroGen Cayman, FibroGen Beijing, and FibroGen International (Hong Kong) Limited (collectively, “FibroGen China”) and AstraZeneca AB (“AstraZeneca”, and together with FibroGen China, the “Parties”) entered into an amendment, effective July 1, 2020, to the China Agreement, relating to the development and commercialization of roxadustat in China (the “Amendment”).

The Amendment provides for the establishment of a jointly owned entity (the “Distribution Entity”) that will perform roxadustat distribution, as well as conduct sales and marketing through AstraZeneca. FibroGen Beijing will continue to hold all of the regulatory licenses issued by China regulatory authorities and will continue to be primarily responsible for regulatory, clinical, manufacturing, medical affairs and pharmacovigilance. In July 2020, the Company closed the acquisition of an entity for the purpose of the establishment of the Distribution Entity.

While the responsibilities of the Parties under the China Agreement remain largely the same, certain changes were made. The Parties have changed the method under which commercial expenses incurred by AstraZeneca are billed, and the collaboration has been adjusted to more fully account for the cost of manufacturing incurred by FibroGen Beijing.

The Company is in the process of evaluating the accounting impacts resulting from the Amendment and the establishment of the Distribution Entity, which is expected to be significant to its consolidated financial statements starting the third quarter of 2020. Among others, the accrued long-term co-promotional expenses related to the estimated amount payable to AstraZeneca for its sales and marketing efforts associated with the commercial launch and sales for roxadustat will be reduced by approximately $82 million in the third quarter of 2020.