Abingworth LLP [Member] Abingworth Limited Liability Partnership [Member] Abingworth LLP Accounting Policies [Abstract] Accounting Policies [Abstract] Accounts Payable and Accrued Liabilities [Line Items] Accounts Payable And Accrued Liabilities [Line Items] Accounts Payable and Accrued Liabilities [Line Items] Accounts Payable and Accrued Liabilities [Table] Accounts Payable And Accrued Liabilities [Table] Accounts Payable and Accrued Liabilities [Table] Accounts Payable Current Accounts payable Accounts Receivable [Member] Accounts Receivable Accounts Receivable Net Current Accounts receivable Accrued Expenses And Other Liabilities Current Accrued Expenses And Other Liabilities Current Accrued expenses and other current liabilities Accrued expenses and other current liabilities Discloses the breakout of accrued expenses and other liabilities that are not individually material for a separate caption on the statement of financial position between the current portion (payable within 12 months of year end or the operating cycle) and non-current (payable after 12 months from year end). Accrued Expenses And Other Liabilities Disclosure [Text Block] Accrued Expenses and Other Current Liabilities Accrued Marketing Costs Current Sales and marketing accruals Accumulated Depreciation Depletion And Amortization Property Plant And Equipment Accumulated depreciation and amortization Additional Paid In Capital Common Stock Additional paid-in capital Additional Paid In Capital [Member] Additional Paid-in Capital Additional Percentage Interest Rate Penalty Additional Percentage Interest Rate Penalty Additional interest rate on notes per annum Additional Square Feet Leased Additional Square Feet Leased Additional office space leased (in square feet) Adjustment For Amortization Amortization expense Adjustments To Additional Paid In Capital Other Transfer of fair value of warrants exercised from liabilities to equity Adjustments To Additional Paid In Capital, Resulting From Conversion Of Convertible Debt Into Equity Adjustments To Additional Paid In Capital Resulting From Conversion Of Convertible Debt Into Equity Conversion option contained in exchangeable notes Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Stock-based compensation Adjustments To Additional Paid In Capital Tax Effect From Share Based Compensation Tax benefits (provisions) from stock-based compensation Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Adjustments to reconcile loss to net cash used in operating activities: Agreement Expiration Date Agreement Expiration Date Agreement expiration date Allowance For Sales Returns [Member] Allowance for Sales Returns Allowance For Trade Receivables [Member] Allowance for Trade Receivables Amarin Pharmaceuticals Ireland Limited [Member] Amarin Pharmaceuticals Ireland Limited [Member] Amarin Pharmaceuticals Ireland Limited Amendment Flag Amendment Flag American Depositary Share American Depositary Share [Member] American Depositary Share American Depository Share [Member] American Depository Share [Member] American Depository Share American Depository Shares [Member] American Depository Shares [Member] American Depository Shares American Depository Shares to Shares Ratio American Depository Shares To Shares Ratio Number of shares that each ADS represents Amortization Of Debt Discount Premium Interest expense, amortization of discount Amortization Of Financing Costs And Discounts Amortization of debt discount and debt issuance costs Amortization Of Intangible Assets Amortization expense Amortization of intangible asset Amr One Hundred One [Member] Amr One Hundred One [Member] Amr One Hundred One Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount Anti-dilutive securities Antidilutive Securities Excluded From Computation Of Earnings Per Share By Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities Name [Domain] Antidilutive Securities, Name [Domain] As Restated [Member] As Restated [Member] As Restated Assets TOTAL ASSETS Assets [Abstract] ASSETS Assets Current Total current assets Assets Current [Abstract] Current Assets: Assets Fair Value Disclosure [Abstract] Asset: Award Type [Axis] Award Type [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Bedminster [Member] Bedminster [Member] Bedminster Biopharmaceutical [Member] Biopharmaceutical [Member] Biopharma Debt Bridge Loan [Member] Bridge Loan Business Acquisition Acquiree [Domain] Business Acquisition, Acquiree [Domain] Business Acquisition [Axis] Business Acquisition Business Development [Domain] Business Development [Domain] Business Development [Domain] Business Developments [Axis] Business Developments [Axis] Business Developments Capitalized Computer Software Gross Software Capital Lease Obligations Total principal obligations Capital Lease Obligations Current Less: current portion Capital Lease Obligations Noncurrent Long-term capital lease Capital Leases Future Minimum Payments Due Total Capital Leases Future Minimum Payments Due [Abstract] Capital Capital Leases Future Minimum Payments Due Current 2014 Capital Leases Future Minimum Payments Due In Five Years 2018 Capital Leases Future Minimum Payments Due In Four Years 2017 Capital Leases Future Minimum Payments Due In Three Years 2016 Capital Leases Future Minimum Payments Due In Two Years 2015 Capital Leases Future Minimum Payments Interest Included In Payments Less: interest Cash And Cash Equivalents At Carrying Value CASH AND CASH EQUIVALENTS, END OF PERIOD CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD Cash and cash equivalents Cash And Cash Equivalents Fair Value Disclosure Cash equivalents - money markets Cash And Cash Equivalents Period Increase Decrease NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS Cash And Cash Equivalents Policy [Text Block] Cash and Cash Equivalents Cash Discount Invoice Terms Cash Discount Invoice Terms Sales discount term Cash Discount Percent Cash Discount Percent Sales discount percentage Cash [Member] Cash Cash Paid During Period For [Abstract] Cash Paid During Period For [Abstract] Cash paid during the year for: Change In Control Obligations Change In Control Obligations Change of control obligation Chemport [Member] Chemport [Member] Chemport Class Of Stock [Domain] Class of Stock [Domain] Class Of Warrant Or Right [Axis] Class of Warrant or Right Class Of Warrant Or Right Common Stock Exchange Ratio Class Of Warrant Or Right Common Stock Exchange Ratio Number of ADS that can be purchased for each warrant received Class Of Warrant Or Right [Domain] Class of Warrant or Right [Domain] Class Of Warrant Or Right Exercise Price Of Warrants Or Rights Exercise Price Class of Warrant or Right, Expiration Date Class Of Warrant Or Right Expiration Date Expiration Date Class of Warrant or Right, Issued Class Of Warrant Or Right Issued Number of warrants issued Class Of Warrant Or Right [Line Items] Class of Warrant or Right [Line Items] Class Of Warrant Or Right Number Of Securities Called By Warrants Or Rights Warrants issued, number of shares called by the warrant Class Of Warrant Or Right Outstanding Amount Number of warrant outstanding Class Of Warrant Or Right [Table] Class of Warrant or Right [Table] Class of Warrant or Right, Term Class Of Warrant Or Right Term Warrant term Commitments And Contingencies Commitments and contingencies (Note 9) Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Line Items] Commitments And Contingencies Disclosure [Line Items] Commitments and Contingencies Disclosure [Line Items] Commitments and Contingencies Disclosure [Table] Commitments And Contingencies Disclosure [Table] Commitments and Contingencies Disclosure [Table] Commitments And Contingencies Disclosure [Text Block] Commitments and Contingencies Commitments [Member] Anticipated investment before the end of 2012 Commitments To Purchase Or Fund Investments Commitments To Purchase Or Fund Investments Minority share equity investment commitment Common Stock [Member] Common Shares Common Stock Par Or Stated Value Per Share Common stock, par Common stock, par value Common Stock Shares Issued Common stock, issued Common Stock Shares Outstanding Common stock, outstanding Common Stock Value Common stock, £0.50 par value, unlimited authorized; 172,691,063 issued, 172,670,984 outstanding at December 31, 2013; 150,360,933 issued, 150,340,854 outstanding at December 31, 2012 Compensation And Employee Benefit Plans [Text Block] Defined Contribution Plan Compensation And Retirement Disclosure [Abstract] Compensation and Retirement Disclosure [Abstract] Component Of Operating Cost And Expense [Line Items] Component Of Operating Cost And Expense [Line Items] Component Of Operating Cost And Expense [Line Items] Component Of Operating Cost And Expense [Table] Component Of Operating Cost And Expense [Table] Component Of Operating Cost And Expense [Table] Computer Equipment and Capitalized Software [Member] Computer Equipment And Capitalized Software [Member] Computer equipment and software Computer equipment, Gross Computer Equipment Gross Computer equipment Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Concentration Risk By Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Credit Risk Concentration of Credit Risk Concentration Risk Percentage 1 Concentration risk percentage Condensed Financial Information Of Parent Company Only Disclosure [Abstract] Condensed Financial Information of Parent Company Only Disclosure [Abstract] Consolidation Policy [Text Block] Principles of Consolidation Construction In Progress Gross Construction in progress Contract Termination [Member] Contract Termination Convertible Debt Convertible notes, carrying amount net of unamortized discount Convertible Debt [Member] Convertible Debt Cost Of Goods Sold Cost of goods sold Cost of goods sold expensed Current Federal Tax Expense Benefit Federal-U.S. Current Fiscal Year End Date Current Fiscal Year End Date Current Income Tax Expense Benefit Total Current Current Income Tax Expense Benefit Continuing Operations [Abstract] Current: Current State And Local Tax Expense Benefit State-U.S. Debt Conversion By Unique Description [Axis] Debt Conversion by Unique Description Debt Conversion Converted Instrument Shares Issued 1 Convertible senior notes, total ADS into which the debt is exchangeable Debt Conversion Name [Domain] Debt Conversion, Name [Domain] Debt Conversion Original Debt Amount 1 Bridge notes converted in conjunction with the private placement, amount Debt Disclosure [Abstract] Debt Disclosure [Abstract] Debt Disclosure [Line Items] Debt Disclosure [Line Items] Debt Disclosure [Line Items] Debt Disclosure [Table] Debt Disclosure [Table] Debt Disclosure [Table] Debt Disclosure [Text Block] Debt Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument Call Date Earliest Convertible senior notes, earliest redemption date Debt Instrument Convertible Conversion Price 1 Bridge notes converted in conjunction with the private placement, price per share Debt Instrument Convertible Conversion Ratio 1 Convertible senior notes, exchange rate of ADS per $1,000 principal amount of notes Debt Instrument Convertible Remaining Discount Amortization Period 1 Debt discount amortization period Debt Instrument Date Of First Required Payment 1 Convertible senior notes, payment start date Debt Instrument Face Amount Convertible senior notes, principal amount Debt Instrument Fair Value Fair value of the liability component Debt Instrument Interest Rate Effective Percentage Effective interest rate Debt Instrument Interest Rate Stated Percentage Convertible senior notes, stated interest rate Debt Instrument Maturity Date Convertible senior notes, maturity date Debt Instrument Maturity Date Year Debt Instrument Maturity Date Year Convertible senior notes, due date Debt Instrument Name [Domain] Debt Instrument, Name [Domain] Debt Instrument Redemption Price Percentage Convertible senior notes, repurchase price at option of the issuer Debt Instrument Term Note, estimated remaining life Debt Instrument Unamortized Discount Unamortized debt discount Debt Issuance Costs Policy [Text Block] Debt Issuance Costs Policy [Text Block] Debt Issuance Costs Debt Offering [Member] Debt Offering [Member] Debt Offering Debt Policy [Text Block] Debt Instruments Deferred Compensation Arrangement With Individual Allocated Share Based Compensation Expense Deferred Stock units, Expenses Deferred Federal Income Tax Expense Benefit Federal-U.S. Deferred Foreign Income Tax Expense Benefit Ireland and United Kingdom Deferred Income Tax Expense Benefit Deferred income taxes Total Deferred Deferred Income Tax Expense Benefit Continuing Operations [Abstract] Deferred: Deferred Revenue Current Deferred product revenue Deferred revenue Deferred Revenue, Policy [Text Block] Deferred Revenue Policy [Text Block] Deferred Revenue Deferred State And Local Income Tax Expense Benefit State-U.S. Deferred Stock Units D S Us [Member] Deferred Stock Units D S Us [Member] Deferred Stock Units (DSUs) Deferred Tax Assets, Depreciation and Amortization Deferred Tax Assets Depreciation And Amortization Depreciation Deferred Tax Assets Gross Gross deferred tax asset Deferred Tax Assets Net Deferred Tax Assets, Net of Valuation Allowance, Total Deferred Tax Assets Net [Abstract] Deferred tax assets: Deferred Tax Assets Net Current Deferred tax assets Deferred Tax Assets Net Noncurrent Deferred tax assets Deferred Tax Assets Operating Loss Carryforwards Net operating losses Deferred Tax Assets Operating Loss Carryforwards Foreign Foreign net operating loss carryforwards Deferred Tax Assets Tax Credit Carryforwards Tax credit carryforwards Tax credits Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost Stock based compensation Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Reserves Other reserves and accrued liabilities Deferred Tax Assets Valuation Allowance Less: valuation allowance Deferred Tax Liabilities, Subject to Expiration Deferred Tax Liabilities Subject To Expiration Gross liabilities to expire in 2014 Defined Benefit Plan Contributions By Employer Contributions made under defined contribution plan Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Depreciation Depreciation expense Depreciation And Amortization Depreciation and amortization Derivative By Nature [Axis] Derivative, by Nature Derivative Contract Type [Domain] Derivative Contract [Domain] Derivative Fair Value Of Derivative Liability Warrant derivative liability, fair value Derivative Instrument [Member] Derivative Instrument [Member] Derivative Instrument Derivative Instrument Risk [Axis] Derivative Instrument [Axis] Derivative Instruments And Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments And Hedging Activities Disclosure [Text Block] Warrants and Warrant Derivative Liability Derivative Liabilities Ending Balance Beginning Balance Warrant derivative liability Derivative Liabilities Current Derivative liability, current Derivative Liabilities Noncurrent Derivative liability Warrant derivative liability Derivative Liabilities Transferred to Stockholders' Equity Derivative Liabilities Transferred To Stockholders Equity Transfers to equity Derivative [Line Items] Derivative [Line Items] Derivative Name [Domain] Derivative, Name [Domain] Derivatives Embedded Derivatives Long Term Debt Redemption Feature Derivatives Fair Value [Line Items] Derivatives, Fair Value [Line Items] Derivatives Policy [Text Block] Derivative Instruments Derivative [Table] Derivative [Table] Development Fees Committed Development Fees Committed Development fees committed Dilutive Securities Effect On Basic Earnings Per Share Other Gain on warrant derivative liability Direct Operating Costs Direct Operating Costs Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Stock Incentive Plans and Stock Based Compensation Document And Entity Information [Abstract] Document And Entity Information [Abstract] Document And Entity Information [Abstract] Document Fiscal Period Focus Document Fiscal Period Focus