Entity Central Index Key Total amount of revenue recognized for license and development 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 Shell Company Entity Shell Company Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Entity Public Float Entity Public Float Restricted time deposits noncurrent. 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 Short Term Investments Accounts receivable ($47,210 and $4,004 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 Long Term Investments 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 ($444 and $272 to a related party) Accrued Liabilities Current Deferred revenue Contract With Customer Liability Current Total current liabilities Liabilities Current Long-term portion of lease financing obligations Finance Lease Liability Noncurrent Product development obligations Accrued Product Development Costs Deferred rent Deferred Rent Credit Noncurrent Deferred revenue, net of current Contract With Customer Liability Noncurrent Other long-term liabilities Other Liabilities Noncurrent Total liabilities Liabilities Commitments and Contingencies Commitments And Contingencies Stockholders’ equity: Stockholders Equity Including Portion Attributable To Noncontrolling Interest [Abstract] Preferred stock, $0.01 par value; 125,000 shares authorized; no shares issued and outstanding at December 31, 2018 and December 31, 2017 Preferred Stock Value Common stock, $0.01 par value; 225,000 shares authorized at December 31, 2018 and December 31, 2017; 85,432 and 82,498 shares issued and outstanding at December 31, 2018 and December 31, 2017 Common Stock Value Additional paid-in capital Additional Paid In Capital 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 party 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 Interest and other net. Income Statement [Abstract] Statement [Table] Statement [Table] Product and Service Product Or Service [Axis] Product and Service Products And Services [Domain] License Revenue [Member] License [Member] Development and other revenue. Development and Other Revenue [Member] Development And Other Revenue [Member] Product Revenue [Member] Product [Member] Statement [Line Items] Statement [Line Items] Revenue: Revenue From Contract With Customer [Abstract] Total revenue Revenue From Contract With Customer Excluding Assessed Tax 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 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. Product revenue from a related party. 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] License and milestone revenue from a related party License Fees And Milestones Revenue Collaboration services and other revenue from a related party Collaboration Services And Other Revenue Product revenue from a related party Product Revenue 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 loss Other Comprehensive Income Loss Reclassification Adjustment From A O C I For Sale Of Securities Net Of Tax Net change in unrealized gain on available-for-sale investments Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax Other comprehensive income (loss), net of taxes Other Comprehensive Income Loss Net Of Tax Comprehensive loss Comprehensive Income Net Of Tax Shares issued from stock plans net of payroll taxes paid shares. Adjustments to additional paid in capital shares issued from stock plans net of payroll taxes paid. Warrant exercised during period shares. Warrants exercised during period value. Statement Of Stockholders Equity [Abstract] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] 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 Interests [Member] Noncontrolling Interest [Member] Adjustments for New Accounting Pronouncements Adjustments For New Accounting Pronouncements [Axis] Type of Adoption Type Of Adoption [Member] ASU 2016-01 [Member] Accounting Standards Update201601 [Member] Balance Balance, Shares Shares Outstanding Impact of change inaccounting principle uponadoption of ASU 2016-01(Note 2) New Accounting Pronouncement Or Change In Accounting Principle Effect Of Change On Net Income Change in unrealized gain or loss on investments Adjustment to issuance costs for Follow-on Offerings Adjustments To Additional Paid In Capital Stock Issued Issuance Costs Follow-on Offerings, net of underwriting discounts, commission and issuance costs Stock Issued During Period Value New Issues Follow-on Offerings, net of underwriting discounts, commission and issuance costs, Shares Stock Issued During Period Shares New Issues Shares issued from stock plans, net of payroll taxes paid Adjustments To Additional Paid In Capital Shares Issued From Stock Plans Net Of Payroll Taxes Paid Shares issued from stock plans, net of payroll taxes paid, Shares Shares Issued From Stock Plans Net Of Payroll Taxes Paid Shares 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 Warrants exercised Warrants Exercised During Period Value Warrants exercised, Shares Warrant Exercised During Period Shares Balance Balance, Shares Unrealized gain loss on cash equivalents and short term equity investments. 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. Payments to acquire available for sale securities and term deposit. Proceeds from follow on offering, net of underwriting discounts and commission costs. Statement Of Cash Flows [Abstract] Operating activities Net Cash Provided By Used In Operating Activities [Abstract] Net loss Profit Loss 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 Net amortization of premium and discount on investments Accretion Amortization Of Discounts And Premiums Investments Unrealized loss on cash equivalents and short-term equity investments Unrealized Gain Loss On Cash Equivalents And Short Term Equity Investments Loss on disposal of property and equipment Gain Loss On Disposition Of Assets Stock-based compensation Share Based Compensation Realized foreign currency gain Foreign Currency Transaction Gain Loss Realized Tax benefit on unrealized gain on available-for-sale securities Other Comprehensive Income Loss Available For Sale Securities Tax 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 ($(43,206), $98 and $353 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 ($172, $(1,343) and $(430) from related party) Increase Decrease In Accrued Liabilities Deferred revenue Increase Decrease In Contract With Customer Liability 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 Investing activities Net Cash Provided By Used In Investing Activities [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 and term deposit Payments To Acquire Available For Sale Securities And Term Deposit Proceeds from sales of available-for-sale securities Proceeds From Sale Of Available For Sale Securities Proceeds from maturities of investments Proceeds From Sale Maturity And Collections Of Investments Net cash provided by (used in) investing activities Net Cash Provided By Used In Investing Activities Financing activities Net Cash Provided By Used In Financing Activities [Abstract] Borrowings under capital lease obligations Proceeds From Long Term Capital Lease Obligations Repayments of capital lease obligations Repayments Of Long Term Capital Lease Obligations Repayments of lease liability Repayments Of Debt And Capital Lease Obligations Proceeds from follow-on offerings, net of underwriting discounts and commission costs Proceeds From Follow On Offering Net Of Underwriting Discounts And Commission Costs 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 Effect of exchange rate change on cash and cash equivalents Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations Net increase (decrease) in cash and cash equivalents Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect Total cash and cash equivalents at beginning of period Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations 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]