Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Statement [Table] Statement [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Class of Warrant or Right [Axis] Class of Warrant or Right [Axis] Class of Warrant or Right [Domain] Class of Warrant or Right [Domain] Warrant Transactions [Member] Warrant Transactions [Member] Warrant transactions entered into in connection with the offering of the convertible senior notes. Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Statement [Line Items] Statement [Line Items] Accrued capital expenditures Accrued Capital Expenditures Carrying value as of the balance sheet date of obligations incurred and payable for purchases of fixed assets. Included in accounts payable and accrued expenses. Convertible Notes Payable, Current Convertible Notes Payable, Current Notes Payable Notes Payable Accounts Payable, Other Accounts Payable, Other Other Liabilities, Fair Value Disclosure Other Liabilities, Fair Value Disclosure Facility lease obligation recognized during the period Facility lease obligation recognized during the period The facility lease obligation recognized during the period. Marketable Securities, Unrealized Gain (Loss) Marketable Securities, Unrealized Gain (Loss) Collaboration Agreement [Abstract] Collaboration Agreement Schedule of Research and Development Arrangement, Contract to Perform for Others [Table] Schedule of Research and Development Arrangement, Contract to Perform for Others [Table] Research and Development Arrangement, Contract to Perform for Others, Type [Axis] Research and Development Arrangement, Contract to Perform for Others, Type [Axis] Research and Development Arrangement, Contract to Perform for Others, Type [Domain] Research and Development Arrangement, Contract to Perform for Others, Type [Domain] Collaboration Agreement with Bayer HealthCare LLC [Member] Collaboration Agreement with Bayer HealthCare LLC [Member] Collaboration agreement with Bayer HealthCare LLC. PDGF PDGF [Member] PDGF [Member] BRVO BRVO [Member] BRVO [Member] Type of Arrangement and Non-arrangement Transactions [Axis] Type of Arrangement and Non-arrangement Transactions [Axis] Arrangements and Non-arrangement Transactions [Domain] Arrangements and Non-arrangement Transactions [Domain] sales achievement - $500 million sales achievement - $500 million [Member] When total aggregate net sales of EYLEA outside the U.S. reaches this level, the Company is eligible to receive the sales milestone. sales achievement - $600 million sales achievement - $600 million [Member] When total aggregate net sales of EYLEA outside the U.S. reaches this level, the Company is eligible to receive the sales milestone. sales achievement - $700 million sales achievement - 700 million [Member] When total aggregate net sales of EYLEA outside the U.S. reaches this level, the Company is eligible to receive the sales milestone. sales achievement - $200 million sales achievement - 200 million [Member] sales achievement - 200 million Collaboration Agreement [Line Items] Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] Number of sales milestone payments the Company received Number of sales milestone payments the Company received Total number of sales milestone payments received during the period after achieving certain sales levels. Revenue Recognition, Milestone Method, Revenue Recognized Revenue Recognition, Milestone Method, Revenue Recognized Levels of twelve month sales at which sales milestone payments were received - 200 million Levels of twelve months sales at which sales milestone payments were received - 200 million In connection with a November 2013 agreement, the Company received additional sales milestone payments if twelve-month sales of specific commercial supplies of EYLEA outside the U.S. achieve certain specified levels up to this level. Levels of twelve month sales at which sales milestone payments were received - 500 million Levels of twelve month sales at which sales milestone payments were received Aggregate amount of twelve month sales upon which sales milestones were received. Levels of twelve month sales at which sales milestone payments were received - 600 million Levels of twelve month sales at which sales milestone payments were received - 600 million Aggregate amount of twelve month sales upon which sales milestone were received. Levels of twelve month sales at which sales milestone payments were received - 700 million Levels of twelve month sales at which sales milestone payments were received - 700 million Aggregate amount of twelve month sales at which sales milestone payments were received - 700 million. Period for Achieving Sales Target for Milestone Payment, Rolling Basis Period for Achieving Sales Target for Milestone Payment, Rolling Basis Period for Achieving Sales Target for Milestone Payment, Rolling Basis Reimbursement of Regeneron research and development expenses Research and Development Arrangement, Contract to Perform for Others, Compensation Earned Other Research and Development Expense Other Research and Development Expense Number of Payments the Company made Number of Payments the Company made Number of Payments Inventory Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Legal Matters Legal Matters and Contingencies [Text Block] Revenues [Abstract] Sales Related Deductions Activity Schedule of Sales Related Deductions Activity [Table Text Block] Tabular disclosure of the activity of sales-related deductions during the period, which may include rebates and chargebacks, and distributor-related fees. Earnings Per Share [Abstract] Basic and Diluted Net Income (Loss) Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Antidilutive Securities Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Statement of Comprehensive Income [Abstract] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Income Statement [Abstract] Income Statement [Abstract] Revenues: Net product sales Sales Revenue, Goods, Net Sanofi collaboration revenue Revenue from Related Parties Bayer HealthCare collaboration revenue Other Collaboration Revenue Revenue realized from sharing of profits/losses on commercialized products, reimbursement of research and development expenses, and other transactions with our collaborator Bayer HealthCare during the period. Technology licensing and other revenue Licenses Revenue Total revenues Revenues Expenses: Costs and Expenses [Abstract] Research and development Research and Development Expense Selling, general, and administrative Selling, General and Administrative Expense Cost of goods sold Cost of Goods Sold Cost of collaboration and contract manufacturing Cost of manufacturing Total cost related to third-party royalties the Company is obligated to pay based on sales of commercial product by the Company’s collaborators, as well as costs in connection with producing commercial supplies for the Company’s collaborators and others. Total expenses Costs and Expenses Income from operations Operating Income (Loss) Other income (expense): Nonoperating Income (Expense) [Abstract] Investment and other income Other Nonoperating Income Interest expense Interest Expense Loss on extinguishment of debt Gains (Losses) on Extinguishment of Debt Total other income (expense) Nonoperating Income (Expense) Income before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Net income Net Income (Loss) Attributable to Parent Net income per share - basic Earnings Per Share, Basic Net income per share - diluted Earnings Per Share, Diluted Weighted average shares outstanding - basic Weighted Average Number of Shares Outstanding, Basic Weighted average shares outstanding - diluted Weighted Average Number of Shares Outstanding, Diluted Statements of Comprehensive Income Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Other comprehensive (loss) income: Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Unrealized (loss) gain on marketable securities, net of tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Praluent and sarilumab [Member] Praluent and sarilumab [Member] Praluent and sarilumab [Member] New Funding New Funding [Member] The new funding under IO Discovery Agreement. Previous Funding under Antibody Discovery Agreement Previous Funding under Antibody Discovery Agreement [Member] The funding under IO Discovery Agreement that would have otherwise been available to the Company under the existing Discovery and Preclinical Development Agreement, which will reduce the funding available in the aggregate under the existing Discovery and Preclinical Development Agreement by such amount. Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Research and Development Arrangement Contract to Perform for Others by Product [Axis] Research and Development Arrangement Contract to Perform for Others by Product [Axis] Research and Development Arrangement Contract to Perform for Others by Product [Axis] Research and Development Arrangement Contract to Perform for Others by Product [Domain] Research and Development Arrangement Contract to Perform for Others by Product [Domain] [Domain] for Research and Development Arrangement Contract to Perform for Others by Product [Axis] ZALTRAP Agreement Aflibercept Agreement [Member] In September 2003, the Company entered into a collaboration agreement (the Aflibercept Agreement) with Aventis Pharmaceuticals Inc. (predecessor to Sanofi), to jointly develop and commercialize aflibercept. Antibody Collaboration Antibody Collaboration [Member] In November 2007, the Company entered into a global, strategic collaboration (the Antibody Collaboration) with Sanofi to discover, develop, and commercialize fully human monoclonal antibodies. IO Discovery Agreement IO Discovery Agreement [Member] In July 2015, the Company entered into a collaboration agreement (Immuno-Oncology agreement) with Sanofi, to jointly develop and commercialize Immuno-Oncology programs. IO License and Collaboration Agreement IO License and Collaboration Agreement [Member] In July 2015, the Company entered into a Immuno-oncology License and Collaboration Agreement (the "IO License and Collaboration Agreement") with Sanofi, to jointly develop and commercialize Immuno-oncology products. Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] PD-1 PD-1 [Member] Programed Cell Death protein 1, or PD-1 ("REGN2810") Number of development milestone payments the Company received Number of development milestone payments the Company received Number of development milestone payments the Company received Percentage of net sales paid by the related party Percentage of aggregate net sales to be paid by the related party in such calendar year Percentage of aggregate net sales to be paid by the related party in such calendar year. Percentage of repayment of development balance out of profits Percentage of development cost for the territory outside the United States previously required to be paid for under the collaboration Percentage of development cost for the territory outside the United States previously required to be paid for under the collaboration. Deferred Revenue, Revenue Recognized Deferred Revenue, Revenue Recognized Licenses Revenue Amount of non refundable payment will receive for collaboration agreement Amount of non refundable payment will receive for collaboration agreement The amount of non-refundable up-front payment the Company will receive in relation to the IO collaboration. Potential future R&D expenses Potential future R&D expenses The total potential amount of research and development expenses the Company may pay to identify and validate potential immuno-oncology targets and develop therapeutic antibodies against such targets through clinical proof-of-concept. Maximum amount of sales milestone payments if total sales achieve specific levels Maximum amount of sales milestone payments if total sales achieve specific levels The maximum amount of sales milestone payments the Company is eligible to receive when and if total annual sales achieve certain specified levels. Levels of twelve month sales at which sales milestone payments would be received Levels of twelve month sales at which sales milestone payments would be received Aggregate amount of twelve month sales upon which sales milestone would be received. Amount of non refundable payment received for collaboration agreement Amount of non refundable payment received for collaboration agreement The amount of non-refundable payment received in relation to the collaboration agreement. May be an up-front payment, termination payment, and/or payment made in connection to an amendment to the agreement. Net profit (loss) from commercialization of products under collaboration agreement Net profit (loss) from commercialization of products under collaboration agreement Our share of profits/losses related to commercialization of products by our collaborator based on sales outside the United States. Under the terms of our collaboration agreement, we share profits/losses with our collaborator on commercialization of products. Recognition of Deferred Revenue Recognition of Deferred Revenue Milestone payment Potential future milestone payments The maximum amount of development milestone payments the Company may pay. Annual funding maximum of research activities per amended agreement Annual funding maximum of research activities per amended agreement The maximum annual amount of funding for research activities through 2017 per the amended agreement. Reduction of Funding for Research Activities Per Agreement Reduction of Funding for Research Activities Per Agreement Reduction of Funding for Research Activities Per Agreement Contracts Revenue Contracts Revenue Revenue from Related Parties Percentage of Trial Costs borne by collaborating party Percentage of Trial Costs borne by collaborating party The percentage of subsequent Shared Phase 3 Trial costs borne by the collaborating party upon receipt of the first positive Phase 3 trial results for a co-developed drug candidate. Percentage of Trial Costs borne by entity Percentage of Trial Costs borne by entity The percentage of subsequent Shared Phase 3 Trial costs borne by the Company upon receipt of the first positive Phase 3 trial results for a co-developed drug candidate. Funding Maximum of Research Activities Per Agreement Funding Maximum of Research Activities Per Agreement The maximum amount of cost reimbursement the Company will receive, subject to certain annual limits. Minimum IO Discovery Agreement Term License agreement term Potential agreement term, from the effective date of agreement. Additional years to extend the agreement Additional years to extend the agreement Additional years to extend the agreement Excess Share of profit not required to to be applied to reimburse development cost Excess Share of profit not required to to be applied to reimburse development cost The excess percentage of profits from collaboration not required to be used to reimburse development cost in any calendar quarter. Maximum amount of shared development costs Maximum amount of shared development costs The maximum amount of shared development expenses for PD-1. Period of Notice to Opt Out of Further Development and or Commercialization Period of Notice to Opt Out of Further Development and or Commercialization The period of notice (in months) for either party under the agreement to opt-out of further development and/or commercialization of each antibody product which enters development. Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Schedule of Error Corrections and Prior Period Adjustments [Table Text Block] Schedule of Error Corrections and Prior Period Adjustments [Table Text Block] Collaboration Agreements Collaborative Arrangement Disclosure [Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Interim Financial Statements Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Investments, Debt and Equity Securities [Abstract] Schedule of Available-for-sale Securities [Table] Classification of Investment [Axis] Classification of Investment [Axis] This element represents the general categories of investments, which may be classified as Unrestricted or Restricted. Classification of Investment [Domain] Classification of Investment [Domain] Provides general categories of investments for which information is required or determined to be disclosed. Unrestricted [Member] Unrestricted [Member] Investments whose use is not restricted in whole or in part, by contractual agreements or regulatory requirements. Restricted [Member] Restricted [Member] Investments whose use is restricted in whole or in part, generally by contractual agreements or regulatory requirements. Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] U.S. government and government agency obligations US Treasury and Government [Member] Corporate bonds U S Government Guaranteed Corporate Bonds [Member] This category includes investments in debt securities issued by corporations that are guaranteed by the U.S. Government. Municipal bonds Municipal Bonds [Member] Equity Securities Equity Securities [Member] Schedule of Available-for-sale Securities [Line Items] Amortized Cost Basis Available-for-sale Securities, Amortized Cost Basis Unrealized Gains Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Unrealized (Losses) Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Total fair value of available-for-sale marketable securities Available-for-sale Securities Available-for-sale Securities, Debt Maturities, Fair Value [Abstract] Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract] Maturities within one year Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value Maturities after one year through five years Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value Maturities after five years through ten years Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value Total Available-for-sale Securities, Debt Securities Continuous Unrealized Loss Position, Fair Value [Abstract] Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Fair Value - Less than 12 Months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Fair Value - 12 Months or Greater Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Fair Value - Total Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Continuous Unrealized Loss Position, Aggregate Losses [Abstract] Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract] Unrealized Loss - Less than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Unrealized Loss - 12 Months or Greater Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Unrealized Loss - Total Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss Inventory Write-down Inventory Write-down Raw materials Inventory, Raw Materials, Net of Reserves Work in process Inventory, Work in Process, Net of Reserves Finished goods Inventory, Finished Goods, Net of Reserves Deferred costs Other Inventory, Net of Reserves Total Inventories Inventory, Net PDGFR-beta outside the US [Member] PDGFR-beta outside the US [Member] PDGFR-beta outside the US Percentage of global development cost to be paid by the collaboration partner under the collaboration Percentage of global development cost to be paid by the collaboration partner under the collaboration Percentage of global development cost to be paid by the collaboration partner under the collaboration Percentage of development cost for the territory outside the United States to be paid for under the collaboration Proceeds from Collaborators Proceeds from Collaborators Percentage of development milestone payments to be reimbursed Percentage of development milestone payments to be reimbursed Percentage of development milestone payments Bayer HealthCare is obligated to reimburse the Company for payments that the Company makes to Sanofi related to the Company's acquisition of rights to antibodies targeting the PDGF family of receptors. Deferred Revenue, Additions Deferred Revenue, Additions Schedule of Inventory, Current Schedule of Inventory, Current [Table Text Block] Available-for-sale Securities Available-for-sale Securities [Table Text Block] Marketable Securities, Based on Contractual Maturity Dates Investments Classified by Contractual Maturity Date [Table Text Block] Fair Value and Unrealized Losses of Marketable Securities Schedule of Unrealized Loss on Investments [Table Text Block] New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Description of New Accounting Pronouncements Not yet Adopted [Text Block] Description of New Accounting Pronouncements Not yet Adopted [Text Block] Legal Costs, Policy [Policy Text Block] Legal Costs, Policy [Policy Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Previously Reported Scenario, Previously Reported [Member] Revision Adjustment Restatement Adjustment [Member] Revised Revised [Member] Represents the revised amount after the correction of an error or other adjustment. Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Deferred tax assets (noncurrent) Deferred Tax Assets, Net, Noncurrent Total assets Assets Additional paid-in-capital Additional Paid in Capital Retained earnings Retained Earnings (Accumulated Deficit) Total stockholders' equity Stockholders' Equity Attributable to Parent Total liabilities and stockholders' equity Liabilities and Equity Total operating expenses Income from operations Income before income taxes Income tax expense Net Income (Loss) Attributable to Parent Net income per share - basic Non-cash compensation expense Share-based Compensation Deferred taxes Deferred Income Tax Expense (Benefit) Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities Effect of dilutive securities: Dilutive Securities, Effect on Basic Earnings Per Share [Abstract] Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Weighted average shares outstanding - basic Effect of dilutive securities (in shares): Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Stock options Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Restricted stock Incremental Common Shares Attributable To Nonvested Restricted Shares Nonvested equity-based payment awards that result in incremental common shares. Warrants Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants Dilutive potential shares Weighted Average Number Diluted Shares Outstanding Adjustment Weighted average shares - diluted (in shares) Earnings Per Share, Basic and Diluted [Abstract] Net income per share - diluted (in dollars per share) Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Stock options Employee Stock Option [Member] Convertible senior notes Convertible Debt Securities [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Weighted average number of shares Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Revenue Recognition, Revenue Reductions [Policy Text Block] Revenue Recognition, Revenue Reductions [Policy Text Block] Collaboration revenue with related party Schedule of Related Party Transactions [Table Text Block] Collaboration revenue Collaboration revenue [Table Text Block] Summary of collaboration revenue [Table Text Block] Marketable Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Document And Entity Information [Abstract] -- None. No documentation exists for this element. -- Entities [Table] Class of Stock [Axis] Class of Stock [Domain] Common Stock Common Stock [Member] Class A Stock Common Class A [Member] Entity Information [Line Items] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Payables and Accruals [Abstract] Accounts Payable and Accrued Liabilities, Current [Abstract] Accounts payable Accounts Payable, Trade, Current Accrued payroll and related costs Employee-related Liabilities, Current Accrued clinical trial expense Accrued Clinical Trial Expense Current Carrying value as of the balance sheet date of obligations incurred (and for which invoices have not been received) in connection with clinical trials. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Accrued sales-related charges, deductions and royalties Accrued sales-related charges, deductions and royalties Carrying value as of the balance sheet date of sales-related charges, deductions and obligations incurred through that date and accrual for royalties. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Other accrued expenses and liabilities Other Accrued Liabilities, Current Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities, Current Fair Value Transfer, Policy [Policy Text Block] Fair Value Transfer, Policy [Policy Text Block] Schedule of Accounts Payable and Accrued Liabilities Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Debt Disclosure [Abstract] Scenario [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Credit Facility [Domain] Credit Facility [Domain] Convertible senior notes Convertible Debt [Member] Debt Conversion Debt Conversion The principal amount of convertible notes that were surrendered for conversion. Debt Instrument, Face Amount Debt Instrument, Face Amount Repayments of convertible senior notes Repayments of Convertible Debt Stock issued during period conversion of convertible notes Stock issued during period conversion of convertible notes Stock issued during the period upon the conversion of convertible securities. Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt, Subsequent Adjustments Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt, Subsequent Adjustments Gains (Losses) on Extinguishment of Debt Loss on extinguishment of debt Loss on extinguishment of debt Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity. Treasury Stock, Shares Treasury Stock, Shares Treasury Stock, Value Treasury Stock, Value Maximum reduction of warrants held by warrant holder Maximum reduction of warrants held by warrant holder Maximum reduction of warrants held by warrant holder pursuant the agreement. Limit price per share for warrant holders to close out hedge position Limit price per share for warrant holders to close out hedge position Limit price per share for warrant holders to close out hedge position pursuant to the agreement. Payments in connection with deduction of outstanding warrants Payments for Repurchase of Warrants Reduction of number of warrants Reduction of number of warrants Reduction of number of warrants Adjustments to Additional Paid in Capital, Warrant Issued Adjustments to Additional Paid in Capital, Other Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Expiration Period Line of Credit Facility, Expiration Period Line of Credit Facility, Increase (Decrease), Net Available increase to the credit facility Maximum available increase to the credit facility Line of Credit Facility, Maximum Month-end Outstanding Amount Line of Credit Facility, Current Borrowing Capacity Line of Credit Facility, Fair Value of Amount Outstanding Line of Credit Facility, Fair Value of Amount Outstanding Statement of Cash Flows Cash Flow, Supplemental Disclosures [Text Block] Accounts Payable and Accrued Expenses Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block] Reduction in accounts receivable Reduction in accounts receivable Reduction in accounts receivable as a result of a revision to previously issued financial statements. Reduction in deferred revenue Reduction in deferred revenue Reduction in deferred revenue as a result of a revision to previously issued financial statements. Reduction in income tax assets, net Reduction in income tax assets, net Reduction in income tax assets, net due to tax impact on prior period adjustment. Reduction in APIC Reduction in APIC Reduction in APIC due to tax impact on prior period adjustment. Increase in total cash from operating Increase in total cash from operating Increase in total cash from operating activities related to the tax impact of the prior period revision. Decrease in total cash from financing Decrease in total cash from financing Decrease in total cash from financing activities related to the tax impact of the prior period revision. Income Tax Disclosure [Abstract] Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Total income tax expense (benefit) Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Effective Income Tax Rate Reconciliation, Change in Tax Rates, Percent Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent Available-for-sale Securities, Income Tax Expense on Change in Unrealized Holding Gain (Loss) Available-for-sale Securities, Income Tax Expense on Change in Unrealized Holding Gain (Loss) EYLEA PDGFR-beta Other Collaboration Revenue Revenue Disclosure [Table] Revenue Disclosure [Table] EYLEA EYLEA Net Product Sales [Member] Revenue during the period derived from a specified product line (EYLEA), after deducting applicable provisions for discounts, returns, rebates, chargebacks, distribution fees, and other sales-related deductions. ARCALYST Arcalyst Net Product Sales [Member] Revenue during the period derived from a specified product line (ARCALYST), after deducting applicable provisions for discounts, returns, rebates, chargebacks, distribution fees, and other sales-related deductions. Concentration Risk Type [Axis] Concentration Risk Type [Domain] Customer concentration risk Customer Concentration Risk [Member] Concentration Risk by Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Gross Sales Revenue GrossSalesRevenue [Member] GrossSalesRevenue [Member] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves [Domain] Valuation Allowances and Reserves [Domain] Rebates and Chargebacks Rebates and Chargebacks [Member] A valuation allowance for rebates and chargebacks under governmental programs (including Medicaid), which are netted against revenue from product sales. Distribution Related Fees Distribution Related Fees [Member] A valuation allowance for distribution-related fees which are netted against revenue from product sales. Other Sales Related Deductions Other Sales Related Deductions [Member] A valuation allowance for other sales-related deductions which are netted against revenue from product sales. Revenue Disclosure [Line Items] Revenues from External Customers and Long-Lived Assets [Line Items] Risks and Uncertainties [Abstract] Risks and Uncertainties [Abstract] Concentration risk, percentage Concentration Risk, Percentage Activity of Sales Related Deductions [Roll Forward] Movement in Valuation Allowances and Reserves [Roll Forward] Balance Valuation Allowances and Reserves, Balance Provision related to current period sales Valuation Allowances and Reserves, Charged to Other Accounts Credits/payments Valuation Allowances and Reserves, Deductions Schedule of assets measured at fair value on a recurring basis Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block] Statement of Financial Position [Abstract] Liabilities and Equity [Abstract] Stockholders' equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Common Stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common Stock, shares authorized (in shares) Common Stock, Shares Authorized Common Stock, shares issued (in shares) Common Stock, Shares, Issued Common Stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Treasury Stock, shares outstanding (in shares) Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Class A Stock Common Stock ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Marketable securities Marketable Securities, Current Accounts receivable - trade, net Accounts Receivable, Net, Current Accounts Receivable from Sanofi Accounts Receivable, Related Parties, Current Accounts receivable from Bayer HealthCare Accounts and Notes Receivable, Net Inventories Deferred tax assets Deferred Tax Assets, Net, Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current Marketable securities Marketable Securities, Noncurrent Property, plant, and equipment, at cost, net of accumulated depreciation and amortization Property, Plant and Equipment, Net Deferred tax assets Other assets Other Assets, Noncurrent Total assets LIABILITIES and STOCKHOLDERS' EQUITY Current liabilities: Liabilities, Current [Abstract] Accounts payable and accrued expenses Deferred revenue from Sanofi, current portion Deferred Revenue From Related Party Current The current portion of deferred revenue from related parties as of balance sheet date. Current deferred revenue is a liability related to a revenue producing activity for which revenue has not yet been recognized, and is expected to be recognized in the next twelve months. Generally, an entity records deferred revenue when it receives consideration before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP. Deferred revenue - other, current portion Deferred Revenue, Current Other Liabilities, Current Other Liabilities, Current Total current liabilities Liabilities, Current Deferred revenue from Sanofi Deferred Revenue From Related Party Noncurrent The noncurrent portion of deferred revenue from related parties as of balance sheet date. Noncurrent deferred revenue is a liability related to a revenue producing activity for which revenue has not yet been recognized, and is not expected to be recognized in the next twelve months. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP. Deferred Revenue - other Deferred Revenue, Noncurrent Facility lease obligations Facility lease obligations noncurrent Represents the noncurrent portion of a lease liability. In connection with the application of FASB authoritative guidance to the Company's lease of newly constructed facilities, the Company is deemed, in substance, to be the owner of the landlord's building; therefore, costs of constructing the facilities that the landlord incurred and reimbursements from the Company's landlord for tenant improvement costs were capitalized, offset by a corresponding lease obligation. Convertible senior notes Convertible Notes Payable, Noncurrent Other long-term liabilities Other Liabilities, Noncurrent Total liabilities Liabilities Preferred Stock Preferred Stock, Value, Issued Common stock Common Stock, Value, Issued Additional paid-in capital Retained earnings Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Treasury stock Total stockholders' equity Total liabilities and stockholders' equity Inventory Inventory Disclosure [Text Block] Income Taxes Income Tax Disclosure [Text Block] Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash (used in) provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Non-cash compensation expense Non-cash interest expense Other Noncash Expense Losses on Extinguishment of Debt Other non-cash charges and expenses, net Other Noncash Income (Expense) Deferred Taxes Increase (Decrease) in Deferred Income Taxes Changes in assets and liabilites Increase (Decrease) in Operating Capital [Abstract] Increase in Sanofi, Bayer HealthCare, and trade accounts receivable Increase (Decrease) in Accounts Receivable Increase in Inventories Increase (Decrease) in Inventories Decrease (increase) in prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets (Decrease) increase in deferred revenue Increase (Decrease) in Deferred Revenue Increase (decrease) in accounts payable, accrued expenses and other liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Total adjustments Net cash (used in) provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Purchases of marketable securities Payments to Acquire Marketable Securities Sales or maturities of marketable securities Proceeds from Sale and Maturity of Marketable Securities Capital expenditures Payments to Acquire Productive Assets Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds (payments) in connection with facility and capital lease obligations Proceeds from (Repayments of) Long-term Debt and Capital Securities Proceeds from issuance of Common Stock Proceeds from Issuance of Common Stock Payments in connection with Common Stock tendered for employee tax obligations Payments Related to Tax Withholding for Share-based Compensation Excess tax benefit from stock-based compensation Excess Tax Benefit from Share-based Compensation, Financing Activities Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Net decrease in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Measured on a recurring basis Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Other than Temporary Impairment Losses, Investments Other than Temporary Impairment Losses, Investments Fair Value, Assets, Level 2 to Level 1 Transfers, Amount Fair Value, Assets, Level 2 to Level 1 Transfers, Amount Convertible Debt, Noncurrent Convertible Debt, Noncurrent Available-for-sale marketable securities: Available-for-sale Securities [Abstract] U.S. government and government agency obligations U S Government Obligations Fair Value Disclosure This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. This item represents available-for-sale securities which consist of investments in U.S. government and government agency obligations neither classified as trading or held-to-maturity securities. Corporate bonds Financial Instruments, Owned, Corporate Debt, at Fair Value Municipal bonds Municipal Debt Securities, at Carrying Value Equity securities Available-for-sale Securities, Equity Securities Total fair value of available-for-sale marketable securities Convertible Debt [Abstract] Convertible Debt [Abstract] Interest rate, stated percentage Debt Instrument, Interest Rate, Stated Percentage Fair value of the outstanding notes Convertible Debt, Fair Value Disclosures Debt Disclosure [Text Block] Debt Disclosure [Text Block] Net Income Per Share Earnings Per Share [Text Block] Product Sales and Concentration Risk [Text Block] Product Sales and Concentration Risk [Text Block] Product Sales and Concentration Risk Disclosure [Text Block]