Entity Central Index Key Total amount of revenue recognized for license and collaboration services under the collaboration agreement as of a given date. Document and entity information. Document And Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well Known Seasoned Issuer Entity Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Entity Public Float Entity Public Float Restricted time deposits noncurrent. Non-current portion of the sum of the obligations recognized by the entity related to lease agreements for which the entity is determined to be the owner of the asset leased for accounting purposes and not legal purposes and the obligations related to not exercising the expansion option under lease agreements. Represents the long-term portion of the outstanding principal and accrued interest of advances in the form note agreements received by the entity to fund various product development efforts. Statement Of Financial Position [Abstract] Assets Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Short-term investments Available For Sale Securities Debt Securities Current Accounts receivable ($4,102 and $4,455 from a related party) Accounts Receivable Net Current Prepaid expenses and other current assets Prepaid Expense And Other Assets Current Total current assets Assets Current Restricted time deposits Restricted Time Deposits Noncurrent Long-term investments Available For Sale Securities Noncurrent Property and equipment, net Property Plant And Equipment Net Other assets Other Assets Noncurrent Total assets Assets Liabilities, stockholders’ equity and non-controlling interests Liabilities And Stockholders Equity [Abstract] Current liabilities: Liabilities Current [Abstract] Accounts payable Accounts Payable Current Accrued liabilities ($1,615 and $2,045 to related parties) Accrued Liabilities Current Deferred revenue Deferred Revenue Current Total current liabilities Liabilities Current Long-term portion of lease financing obligations Lease Financing Obligation Noncurrent Product development obligations Accrued Product Development Costs Deferred rent Deferred Rent Credit Noncurrent Deferred revenue, net of current Deferred Revenue Noncurrent Other long-term liabilities Other Liabilities Noncurrent Total liabilities Liabilities Commitments and Contingencies (Note 8) Commitments And Contingencies Stockholders’ equity: Stockholders Equity Including Portion Attributable To Noncontrolling Interest [Abstract] Preferred stock, $0.01 par value; 125,000 shares authorized at December 31, 2016 and December 31, 2015; no shares issued and outstanding at December 31, 2016 and December 31, 2015 Preferred Stock Value Common stock, $0.01 par value; 225,000 shares authorized at December 31, 2016 and December 31, 2015; 63,665 and 61,985 shares issued and outstanding at December 31, 2016 and December 31, 2015 Common Stock Value Stockholders' notes receivable Stockholders Equity Note Subscriptions Receivable Additional paid-in capital Additional Paid In Capital Common Stock Accumulated other comprehensive loss Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated deficit Retained Earnings Accumulated Deficit Total stockholders’ equity Stockholders Equity Non-controlling interests Minority Interest Total equity Stockholders Equity Including Portion Attributable To Noncontrolling Interest Total liabilities, stockholders’ equity and non-controlling interests Liabilities And Stockholders Equity Accounts receivable from related party Accounts Receivable Related Parties Current Accrued liabilities to related parties Due To Related Parties Current Preferred stock, par value Preferred Stock Par Or Stated Value Per Share Preferred stock, shares authorized Preferred Stock Shares Authorized Preferred stock, shares issued Preferred Stock Shares Issued Preferred stock, shares outstanding Preferred Stock Shares Outstanding Common stock, par value Common Stock Par Or Stated Value Per Share Common stock, shares authorized Common Stock Shares Authorized Common stock, shares issued Common Stock Shares Issued Common stock, shares outstanding Common Stock Shares Outstanding Revenue from multiple-deliverable arrangements that include licensing fees and services revenue and the amount of consideration recognized during the period for milestones. Licensing revenue is consideration received from another party for the right to use, but not own, certain of the entity's intangible assets. Licensing arrangements include, but are not limited to, rights to use a patent, copyright, technology, manufacturing process, software or trademark. Licensing fees are generally, but not always, fixed as to amount and not dependent upon the revenue generated by the licensing party. An entity may receive licensing fees for licenses that also generate royalty payments to the entity. Services revenue may be derived by providing other, non-specified, services during the reporting period. Revenue recognized from co-development services, manufacturing of clinical supplies, committee services and information services and other revenue. Interest and other net. Income Statement [Abstract] Revenue: Revenues [Abstract] License and milestone revenue (includes $24,421, $18,701 and $14,453 from a related party) License Fees And Milestones Revenue Collaboration services and other revenue (includes $1,357, $2,895 and $3,535 from a related party) Collaboration Services And Other Revenue Total revenue Revenues Operating expenses: Operating Expenses [Abstract] Research and development Research And Development Expense General and administrative General And Administrative Expense Total operating expenses Operating Expenses Loss from operations Operating Income Loss Interest and other, net Interest And Other Net [Abstract] Interest expense Interest Expense Interest income and other, net Interest And Other Income Total interest and other, net Interest Income Expense Nonoperating Net Loss before income taxes Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Provision for (benefit from) income taxes Income Tax Expense Benefit Net loss Net Income Loss Net loss per share - basic and diluted Earnings Per Share Basic And Diluted Weighted average number of common shares used to calculate net loss per share - basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Statement [Table] Statement [Table] Type of Arrangement and Non-arrangement Transactions Type Of Arrangement [Axis] Arrangements and Non-arrangement Transactions Arrangements And Nonarrangement Transactions [Member] Astellas agreements. Astellas Agreement [Member] Astellas Collaboration Agreement [Member] Statement [Line Items] Statement [Line Items] License and milestone revenue from a related party Collaboration services and other revenue from a related party Statement Of Income And Comprehensive Income [Abstract] Net loss Other comprehensive income (loss): Other Comprehensive Income Loss Net Of Tax Period Increase Decrease [Abstract] Foreign currency translation adjustments Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax Available-for-sale investments: Other Comprehensive Income Available For Sale Securities Adjustment Net Of Tax Period Increase Decrease [Abstract] Unrealized gain (loss) on investments, net of tax effect Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax Reclassification from accumulated other comprehensive gain (loss) Other Comprehensive Income Loss Reclassification Adjustment From A O C I For Sale Of Securities Net Of Tax Net change in unrealized gain (loss) on available-for-sale investments Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax Other comprehensive income, net of taxes Other Comprehensive Income Loss Net Of Tax Comprehensive loss Comprehensive Income Net Of Tax The value of Convertible securities that were converted in the period. The number of Convertible securities that were converted in the period. Private placement. Private placement shares. Shares issued upon vesting of restricted stock units net of payroll taxes paid and purchases made under the employee stock purchase plan. Shares issued upon vesting of restricted stock units net of payroll taxes paid and purchases made under the employee stock purchase plan shares. Adjustments to additional paid in capital stock issued issuance costs and sale of common stock. Warrants exercised during period value. Warrant exercised during period shares. Statement Of Stockholders Equity [Abstract] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Senior preferred stock. Senior Preferred Stock [Member] Senior Preferred Stock [Member] Junior preferred stock. Junior Preferred Stock [Member] Junior Preferred Stock [Member] Common Stock [Member] Common Stock [Member] Additional Paid-in Capital [Member] Additional Paid In Capital [Member] Accumulated Other Comprehensive Loss [Member] Accumulated Other Comprehensive Income [Member] Accumulated Deficit [Member] Retained Earnings [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Legal Entity Legal Entity [Axis] Entity Entity [Domain] Fibro Gen Europe Oy. FibroGen Europe [Member] Fibrogen Europe Oy [Member] Related Party Related Party Transactions By Related Party [Axis] Related Party Related Party [Domain] AstraZeneca. Astra Zeneca [Member] Astra Zeneca [Member] Balance Balance, Shares Shares Outstanding Change in unrealized loss on investments Stock options exercised Stock Issued During Period Value Stock Options Exercised Stock options exercised, Shares Stock Issued During Period Shares Stock Options Exercised Shares issued upon vesting of restricted stock units, net of payroll taxes paid, and purchases made under the employee stock purchase plan Shares Issued Upon Vesting Of Restricted Stock Units Net Of Payroll Taxes Paid And Purchases Made Under The Employee Stock Purchase Plan Shares issued upon vesting of restricted stock units, net of payroll taxes paid, and purchases made under the employee stock purchase plan, shares Shares Issued Upon Vesting Of Restricted Stock Units Net Of Payroll Taxes Paid And Purchases Made Under The Employee Stock Purchase Plan Shares True up of issuance costs related to initial public offering and common stock sold by FibroGen Europe Adjustments To Additional Paid In Capital Stock Issued Issuance Costs And Sale Of Common Stock Stock appreciation rights settled Stock Issued During Period Value Share Based Compensation Stock appreciation rights settled, Shares Stock Issued During Period Shares Share Based Compensation Stock-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Conversion of preferred stock to common stock Stock Issued During Period Value Conversion Of Convertible Securities Conversion of preferred stock to common stock Stock Converted During Period Value Of Convertible Securities Converted Conversion of preferred stock to common stock, shares Stock Issued During Period Shares Conversion Of Convertible Securities Conversion of preferred stock to common stock, shares Stock Converted During Period Shares Of Convertible Securities Converted Initial Public Offering, net of underwriting discounts, commission and issuance costs Stock Issued During Period Value New Issues Initial Public Offering, net of underwriting discounts, commission and issuance costs, shares Stock Issued During Period Shares New Issues Astra Zeneca private placement Private Placement Astra Zeneca private placement, Shares Private Placement Shares Warrants exercised Warrants Exercised During Period Value Warrants exercised, Shares Warrant Exercised During Period Shares Balance Balance, Shares Increase (decrease) in the obligation recognized by the entity related to lease agreements for which the entity is determined to be the owner of the asset leased for accounting purposes and not legal purposes. Proceeds from initial public offering, net of underwriting discounts and commission costs. Statement Of Cash Flows [Abstract] Operating activities Net Cash Provided By Used In Operating Activities Continuing Operations [Abstract] Adjustments to reconcile net loss to net cash provided by / (used in) operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Depreciation Depreciation Amortization of premium on investments Investment Income Amortization Of Premium Loss on disposal of property and equipment Gain Loss On Disposition Of Assets Stock-based compensation Share Based Compensation Tax benefit on unrealized gain on available-for-sale securities Available For Sale Securities Income Tax Expense On Change In Unrealized Holding Gain Or Loss Realized gain on sales of available-for-sale securities Availableforsale Securities Gross Realized Gain Loss Excluding Other Than Temporary Impairments Changes in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Accounts receivable ($353, $578 and $979 from related party) Increase Decrease In Accounts Receivable Prepaid expenses and other current assets Increase Decrease In Prepaid Deferred Expense And Other Assets Other assets Increase Decrease In Other Operating Assets Accounts payable Increase Decrease In Accounts Payable Accrued liabilities ($(430), $(2,549) and $1,828 from related party) Increase Decrease In Accrued Liabilities Deferred revenue Increase Decrease In Deferred Revenue Lease financing liability Increase Decrease In Lease Financing Liability Other long-term liabilities Increase Decrease In Other Noncurrent Liabilities Net cash provided by (used in) operating activities Net Cash Provided By Used In Operating Activities Continuing Operations Investing activities Net Cash Provided By Used In Investing Activities Continuing Operations [Abstract] Purchases of property and equipment Payments To Acquire Property Plant And Equipment Proceeds from sale of property and equipment Proceeds From Sale Of Property Plant And Equipment Purchases of available-for-sale securities Payments To Acquire Available For Sale Securities Proceeds from sales of available-for-sale securities Proceeds From Sale Of Available For Sale Securities Proceeds from maturities of available-for-sale securities Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities Net cash provided by (used in) investing activities Net Cash Provided By Used In Investing Activities Continuing Operations Financing activities Net Cash Provided By Used In Financing Activities Continuing Operations [Abstract] Repayments of lease liability Repayments Of Long Term Capital Lease Obligations Proceeds from initial public offering, net of underwriting discounts and commission costs Proceeds From Initial Public Offering Net Of Underwriting Discounts And Commission Costs Proceeds from AstraZeneca private placement Proceeds From Issuance Of Private Placement Cash paid for payroll taxes on restricted stock unit releases Payments Related To Tax Withholding For Share Based Compensation Proceeds from issuance of common stock Proceeds From Issuance Of Common Stock Payments of deferred offering costs Payments Of Stock Issuance Costs Net cash provided by financing activities Net Cash Provided By Used In Financing Activities Continuing Operations Effect of exchange rate change on cash and cash equivalents Effect Of Exchange Rate On Cash And Cash Equivalents Continuing Operations Net increase (decrease) in cash and cash equivalents Cash And Cash Equivalents Period Increase Decrease Total cash and cash equivalents at beginning of period Total cash and cash equivalents at end of period Supplemental cash flow information: Supplemental Cash Flow Information [Abstract] Interest payments Interest Paid Net Balance in accounts payable and accrued liabilities related to purchases of property and equipment Capital Expenditures Incurred But Not Yet Paid Deferred offering costs recorded in accounts payable and accrued liabilities Liabilities Assumed1 Accounts receivable from related party Increase Decrease In Accounts Receivable Related Parties Accrued liabilities from related party Increase Decrease In Accounts Payable Related Parties Organization Consolidation And Presentation Of Financial Statements [Abstract] The Company Business Description And Basis Of Presentation [Text Block] Accounting Policies [Abstract] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Collaboration Agreements Collaborative Arrangement Disclosure [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Balance Sheet Components Supplemental Balance Sheet Disclosures [Text Block] Product development obligation disclosure. Debt Disclosure [Abstract] Product Development Obligations Product Development Obligations Disclosure [Text Block] Convertible Note Payable Debt Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments And Contingencies Disclosure [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Equity and Stock-based Compensation Shareholders Equity And Share Based Payments [Text Block] Earnings Per Share [Abstract] Net Loss Per Share Earnings Per Share [Text Block] Compensation And Retirement Disclosure [Abstract] FibroGen, Inc. 401(k) Plan Pension And Other Postretirement Benefits Disclosure [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block]