Equity - Common Stock - Additional Information (Detail) - shares	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022
Amarin Corporation Plc 2017 Employee Stock Purchase Plan \| Ordinary Shares
Stockholders Equity Note [Line Items]
Issuance of common stock under employee stock purchase plan (in shares)	205,861	265,214

Number of shares issued during the period as a result of an employee stock purchase plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
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-SubTopic 10
-Topic 505
-Publisher FASB
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
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-Subparagraph (SX 210.5-02(28))
-Publisher FASB
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
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-Name Accounting Standards Codification
-Section S99
-Paragraph 1
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-Publisher FASB
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Name:	us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration