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Income Taxes - Additional Information (Detail) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Income Taxes [Line Items] |  |  |
Total amount of unrecognized tax benefits that would affect the tax rate if recognized | $ 8,900,000 | $ 8,200,000 |
Interest related to uncertain tax positions | 700,000 | 500,000 |
Penalties related to uncertain tax positions | 0 | 0 |
Gross liabilities to expire in 2024 | 0 |  |
Decrease in net operating loss carryforwards from prior years | 125,600,000 |  |
Tax credit carryforwards | 2,409,000 | 2,639,000 |
Undistributed earning retained indefinitely for reinvestment by foreign subsidiary | 0 |  |
Unrecognized deferred income tax liability | 0 |  |
ASU No. 2016-09 |  |  |
Income Taxes [Line Items] |  |  |
Provisions benefit for income taxes | $ 0 | $ 600,000 | $ 100,000
Ireland |  |  |
Income Taxes [Line Items] |  |  |
Corporate tax rate | 25.00% | 25.00% | 25.00%
Ireland | Amarin Pharmaceuticals Ireland Limited |  |  |
Income Taxes [Line Items] |  |  |
Corporate tax rate | 12.50% | 12.50% | 12.50%
Ireland | Non-Trading Activity |  |  |
Income Taxes [Line Items] |  |  |
Corporate tax rate | 25.00% |  |
Ireland | Trading Activity |  |  |
Income Taxes [Line Items] |  |  |
Corporate tax rate | 12.50% |  |
U.S. and Non-U.S. |  |  |
Income Taxes [Line Items] |  |  |
Foreign net operating loss carryforwards | $ 959,900,000 |  |
U.S. Federal |  |  |
Income Taxes [Line Items] |  |  |
Tax credit carryforwards | 8,600,000 |  |
State |  |  |
Income Taxes [Line Items] |  |  |
Tax credit carryforwards | $ 3,500,000 |  |
State | Minimum |  |  |
Income Taxes [Line Items] |  |  |
Tax credit carryforward expiration year | 2025 |  |
State | Maximum |  |  |
Income Taxes [Line Items] |  |  |
Tax credit carryforward expiration year | 2043 |  |

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