XML 40 R61.htm IDEA: XBRL DOCUMENT v2.4.1.9

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Taxes [Line Items]
Total amount of unrecognized tax benefits that would affect the tax rate if recognized	1,400,000us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	1,700,000us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate
Gross liabilities to expire in 2015	439,000amrn_DeferredTaxLiabilitiesSubjectToExpiration
Decrease in net operating loss carryforwards from prior years	14,900,000amrn_DeferredTaxAssetsOperatingLossCarryforwardsChangeInAmount
Tax credit carryforwards	2,141,000us-gaap_DeferredTaxAssetsTaxCreditCarryforwards	1,256,000us-gaap_DeferredTaxAssetsTaxCreditCarryforwards
Income tax benefit to be recognized in the fourth quarter of 2014	1,400,000us-gaap_OtherTaxExpenseBenefit
Ireland
Income Taxes [Line Items]
Corporate tax rate	25.00%amrn_StatutoryTaxRate / us-gaap_IncomeTaxAuthorityAxis = country_IE	25.00%amrn_StatutoryTaxRate / us-gaap_IncomeTaxAuthorityAxis = country_IE	25.00%amrn_StatutoryTaxRate / us-gaap_IncomeTaxAuthorityAxis = country_IE
Ireland | Amarin Pharmaceuticals Ireland Limited
Income Taxes [Line Items]
Corporate tax rate	12.50%amrn_StatutoryTaxRate / us-gaap_IncomeTaxAuthorityAxis = country_IE / dei_LegalEntityAxis = amrn_AmarinPharmaceuticalsIrelandLimitedMember	12.50%amrn_StatutoryTaxRate / us-gaap_IncomeTaxAuthorityAxis = country_IE / dei_LegalEntityAxis = amrn_AmarinPharmaceuticalsIrelandLimitedMember	12.50%amrn_StatutoryTaxRate / us-gaap_IncomeTaxAuthorityAxis = country_IE / dei_LegalEntityAxis = amrn_AmarinPharmaceuticalsIrelandLimitedMember
Ireland | Non-Trading Activity
Income Taxes [Line Items]
Corporate tax rate	25.00%amrn_StatutoryTaxRate / us-gaap_IncomeTaxAuthorityAxis = country_IE / amrn_TaxesByNatureAxis = amrn_NonTradingActivityMember
Ireland | Trading Activity
Income Taxes [Line Items]
Corporate tax rate	12.50%amrn_StatutoryTaxRate / us-gaap_IncomeTaxAuthorityAxis = country_IE / amrn_TaxesByNatureAxis = amrn_TradingActivityMember
Republic of Ireland, United Kingdom and Israel
Income Taxes [Line Items]
Foreign net operating loss carryforwards	513,300,000us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsForeign / us-gaap_IncomeTaxAuthorityAxis = amrn_RepublicOfIrelandUnitedKingdomAndIsraelMember
U.S. Federal
Income Taxes [Line Items]
Tax credit carryforwards	6,200,000us-gaap_DeferredTaxAssetsTaxCreditCarryforwards / us-gaap_IncomeTaxAuthorityAxis = us-gaap_DomesticCountryMember
U.S. Federal | Ester Neurosciences Ltd | Minimum
Income Taxes [Line Items]
U.S Federal tax credit carryforwards, expiration date	2020
U.S. Federal | Ester Neurosciences Ltd | Maximum
Income Taxes [Line Items]
U.S Federal tax credit carryforwards, expiration date	2034
State
Income Taxes [Line Items]
Tax credit carryforwards	1,400,000us-gaap_DeferredTaxAssetsTaxCreditCarryforwards / us-gaap_IncomeTaxAuthorityAxis = us-gaap_StateAndLocalJurisdictionMember

X

- Definition

Deferred Tax Assets, Operating Loss Carryforwards, Change In Amount

+ References

No definition available.

+ Details

Name:	amrn_DeferredTaxAssetsOperatingLossCarryforwardsChangeInAmount
Namespace Prefix:	amrn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Deferred Tax Liabilities, Subject to Expiration

+ References

No definition available.

+ Details

Name:	amrn_DeferredTaxLiabilitiesSubjectToExpiration
Namespace Prefix:	amrn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Details

Name:	amrn_IncomeTaxesLineItems
Namespace Prefix:	amrn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Statutory Tax Rate

+ References

No definition available.

+ Details

Name:	amrn_StatutoryTaxRate
Namespace Prefix:	amrn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tax Credit Carryforward, Expiration Year

+ References

No definition available.

+ Details

Name:	amrn_TaxCreditCarryforwardExpirationYear
Namespace Prefix:	amrn_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible foreign operating loss carryforwards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32621-109319



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32632-109319



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 25

-Paragraph 20

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=29652012&loc=d3e28680-109314

+ Details

Name:	us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsForeign
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The tax effect as of the balance sheet date of the amount of future tax deductions arising from all unused tax credit carryforwards which have been reduced by a valuation allowance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32621-109319



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32632-109319



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Carryforwards

-URI http://asc.fasb.org/extlink&oid=6506874

+ Details

Name:	us-gaap_DeferredTaxAssetsTaxCreditCarryforwards
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of other income tax expense (benefit).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Article 4



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32672-109319



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(h)(1))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_OtherTaxExpenseBenefit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

+ Details

Name:	us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=amrn_RepublicOfIrelandUnitedKingdomAndIsraelMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=country_IE
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=us-gaap_DomesticCountryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=us-gaap_StateAndLocalJurisdictionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: