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Discontinued Operations and Divestiture - Additional Information (Detail) - USD ($) $ in Thousands |  |  | 3 Months Ended | 9 Months Ended |
--- | --- | --- | --- | --- | ---
Nov. 06, 2025 | Aug. 29, 2025 | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | Dec. 31, 2024
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Gain on divestiture |  |  |  |  | $ 52,163 | $ 0 |
Accounts receivable from related parties |  |  | $ 121 |  | 121 |  | $ 481
Share Purchase Agreement [Member] |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Discontinued operation consideration |  | $ 220,400 |  |  |  |  |
Discontinued operation cash paid at closing |  | 210,400 |  |  |  |  |
Discontinued operation other receivable |  |  | 10,000 |  | $ 10,000 |  |
Falikang [Member] |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Percentage of outstanding shares owned |  |  |  |  | 51.10% |  |
Investment income (loss) |  |  | 1,400 | $ 900 | $ 2,500 | 2,700 |
Equity method investments |  |  |  |  |  |  | 6,900
Accounts receivable from related parties |  |  |  |  |  |  | $ 13,900
Falikang [Member] | Collaborative Arrangement [Member] |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Revenues |  |  | 165,300 | 42,200 | $ 218,600 | 115,300 |
Increase in revenue |  |  | 118,300 |  |  |  |
AstraZeneca [Member] | Share Purchase Agreement [Member] |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Discontinued operation cash payable at closing subject to holdbacks |  | 10,000 |  |  |  |  |
Discontinued operation hold back amount to offset final net cash adjustments |  | 6,000 |  |  |  |  |
Discontinued operation, hold back amount to satisfy any indemnity claims |  | 4,000 |  |  |  |  |
AstraZeneca [Member] | Share Purchase Agreement [Member] | Subsequent Event [Member] |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Disposal group including discontinued operation additional payment following final net cash adjustments after closing | $ 400 |  |  |  |  |  |
Discontinued operation hold back amount received as final net cash adjustments | $ 6,400 |  |  |  |  |  |
FibroGen International [Member] |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Description of discontinued operations |  |  |  |  | On February 20, 2025, the Company entered into the Share Purchase Agreement with AstraZeneca Treasury Limited, pursuant to which FibroGen and its subsidiary FibroGen China Anemia Holdings, Ltd. agreed to sell all of the issued and outstanding equity interests of FibroGen International to AstraZeneca Treasury Limited. This sale includes all of our roxadustat assets in China, including FibroGen International’s subsidiary FibroGen Beijing and its 51.1% interest in Falikang. The Company determined that FibroGen International met the “held for sale” criteria and the “discontinued operations” criteria in accordance with FASB ASC 205, Presentation of Financial Statements, as of December 31, 2024. Accordingly, the operating results related to the FibroGen International are classified as discontinued operations, and have been reflected as discontinued operations in the condensed consolidated statements of operations, while the related assets and liabilities were classified within the condensed consolidated balance sheets as held for sale for all periods presented. |  |
Discontinued operations name |  |  |  |  | FibroGen International |  |
Gain on divestiture |  | 52,200 | $ 52,163 | $ 0 | $ 52,163 | $ 0 |
FibroGen International [Member] | Share Purchase Agreement [Member] |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Discontinued operation consideration |  | 220,400 |  |  |  |  |
Discontinued operation consideration in cash |  | 85,000 |  |  |  |  |
Discontinued operation consideration transaction costs and fees |  | 7,800 |  |  |  |  |
Discontinued operation derecognition of net equity |  | 154,900 |  |  |  |  |
Discontinued operatiion cumulative currency translation adjustments |  | 5,500 |  |  |  |  |
Net Cash Held in China [Member] | Share Purchase Agreement [Member] |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Discontinued operation consideration in cash |  | $ 135,400 |  |  |  |  |

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