XML 73 R39.htm IDEA: XBRL DOCUMENT
v3.22.4

Significant Accounting Policies - Estimated Fair Value of Assets and Liability (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands | Dec. 31, 2022 | Dec. 31, 2021
--- | --- | ---
Asset: |  |
Asset, fair value | $ 192,307 | $ 374,911
Level 1 |  |
Asset: |  |
Asset, fair value | 86,541 | 118,282
Level 2 |  |
Asset: |  |
Asset, fair value | 105,766 | 256,629
Money Market Fund |  |
Asset: |  |
Asset, fair value | 81,870 | 95,063
Money Market Fund | Level 1 |  |
Asset: |  |
Asset, fair value | 81,870 | 95,063
U.S. Treasury Shares |  |
Asset: |  |
Asset, fair value | 3,117 | 23,219
U.S. Treasury Shares | Level 1 |  |
Asset: |  |
Asset, fair value | 3,117 | 23,219
Agency Securities |  |
Asset: |  |
Asset, fair value | 1,554 |
Agency Securities | Level 1 |  |
Asset: |  |
Asset, fair value | 1,554 |
Corporate Bonds |  |
Asset: |  |
Asset, fair value | 28,416 | 83,587
Corporate Bonds | Level 2 |  |
Asset: |  |
Asset, fair value | 28,416 | 83,587
Commercial Paper |  |
Asset: |  |
Asset, fair value | 62,347 | 121,773
Commercial Paper | Level 2 |  |
Asset: |  |
Asset, fair value | 62,347 | 121,773
Repo Securities |  |
Asset: |  |
Asset, fair value | 3,250 | 8,000
Repo Securities | Level 2 |  |
Asset: |  |
Asset, fair value | 3,250 | 8,000
Asset Backed Securities |  |
Asset: |  |
Asset, fair value | 1,260 | 8,816
Asset Backed Securities | Level 2 |  |
Asset: |  |
Asset, fair value | 1,260 | 8,816
Certificate of Deposit |  |
Asset: |  |
Asset, fair value | 9,100 | 21,553
Certificate of Deposit | Level 2 |  |
Asset: |  |
Asset, fair value | 9,100 | 21,553
Non-US Government |  |
Asset: |  |
Asset, fair value | 1,393 | 12,900
Non-US Government | Level 2 |  |
Asset: |  |
Asset, fair value | $ 1,393 | $ 12,900

X
- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258 + Details
Name: | us-gaap_AssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_AssetsFairValueDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=amrn_AgencySecurityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_CommercialPaperMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=amrn_RepoSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_CertificatesOfDepositMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |