XML 14 R39.htm IDEA: XBRL DOCUMENT
v3.20.1

Co-Promotion Agreement - Additional Information (Detail) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2020 | Dec. 31, 2018 | Dec. 31, 2019
Co Promotion Agreement [Line Items] |  |  |
Accrued expenses and other current liabilities | $ 170,731 |  | $ 139,826
Co-Promotion Agreement | Kowa Pharmaceuticals America, Inc. |  |  |
Co Promotion Agreement [Line Items] |  |  |
Agreement amended date | Jul. 25, 2017 |  |
Promotion fee as a percentage of gross margin |  | 18.50% |
Maximum co-promotion tail payments receive period | 3 years |  |
Co-promotion tail payments receivable |  | $ 17,800 |
Accrued co- promotion tail payments |  | $ 16,600 |
Accrued expenses and other liabilities | $ 7,700 |  | 10,000
Accrued expenses and other current liabilities | $ 5,300 |  | $ 6,500

X
- Definition Accrued co promotion tail payments. + References No definition available. + Details
Name: | amrn_AccruedCoPromotionTailPayments
Namespace Prefix: | amrn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Accrued liabilities and other liabilities current. + References No definition available. + Details
Name: | amrn_AccruedLiabilitiesAndOtherLiabilitiesCurrent
Namespace Prefix: | amrn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Agreement amended date. + References No definition available. + Details
Name: | amrn_AgreementAmendedDate
Namespace Prefix: | amrn_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Co-promotion agreement. + References No definition available. + Details
Name: | amrn_CoPromotionAgreementLineItems
Namespace Prefix: | amrn_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Co-Promotion tail payments receivable. + References No definition available. + Details
Name: | amrn_CoPromotionTailPaymentsReceivable
Namespace Prefix: | amrn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Maximum co-promotion tail payments receive period. + References No definition available. + Details
Name: | amrn_MaximumCoPromotionTailPaymentsReceivePeriod
Namespace Prefix: | amrn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of gross margin, payable for promotion agreement. + References No definition available. + Details
Name: | amrn_PercentageOfGrossMarginPayableForPromotionAgreement
Namespace Prefix: | amrn_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of expenses incurred but not yet paid nor invoiced, and liabilities classified as other. + References No definition available. + Details
Name: | us-gaap_AccruedLiabilitiesAndOtherLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=amrn_CoPromotionAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=amrn_KowaPharmaceuticalsAmericaIncorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |