Area under sub-lease agreement.

No definition available.

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Period Type:	instant

- Definition

Lease annual rent paid

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Lease operating sublease commencement date.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Number of renewal options.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Operating lease change in weighted average discount rate percent.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Operating lease commencement date.

+ References

No definition available.

+ Details

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Namespace Prefix:	amrn_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Operating lease commencement end

+ References

No definition available.

+ Details

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Namespace Prefix:	amrn_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Operating Lease Commencement Start Date.

+ References

No definition available.

+ Details

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Namespace Prefix:	amrn_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Operating lease termination date.

+ References

No definition available.

+ Details

Name:	amrn_OperatingLeaseTerminationDate
Namespace Prefix:	amrn_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Short term lease period.

+ References

No definition available.

+ Details

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Namespace Prefix:	amrn_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Area of land held.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 970
-SubTopic 360
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-28(Column A)(Footnote 2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478979/970-360-S99-1

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Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of lessee's operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
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Balance Type:	na
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- Definition

Indicates (true false) whether lessee has option to terminate operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 20
-Name Accounting Standards Codification
-Section 50
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Balance Type:	na
Period Type:	duration

- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S99
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Description of terms and conditions of option to terminate lessee's operating lease. Includes, but is not limited to, information about option recognized as part of right-of-use asset and lease liability.

+ References

+ Details

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- Definition

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

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- Definition

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

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- Definition

Amount of lease payments to be received by lessor for operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
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-URI https://asc.fasb.org/1943274/2147479773/842-30-50-12

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Balance Type:	debit
Period Type:	instant

- Definition

Amount of operating lease expense. Excludes sublease income.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Section 45
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Balance Type:	debit
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- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

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Balance Type:	credit
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- Definition

Amount of lessee's right to use underlying asset under operating lease.

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- Definition

Weighted average discount rate for operating lease calculated at point in time.

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Data Type:	dtr-types:percentItemType
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Period Type:	instant

- Details

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Leases - Additional Information (Detail) $ in Thousands							3 Months Ended		9 Months Ended
Leases - Additional Information (Detail) $ in Thousands	Sep. 04, 2026	Mar. 01, 2025 USD ($)	Sep. 01, 2024 USD ($)	Feb. 01, 2023 USD ($)	Feb. 01, 2022 USD ($) RenewalOption	Aug. 15, 2019 USD ($) RenewalOption	Sep. 30, 2026 USD ($)	Sep. 30, 2025 USD ($)	Sep. 30, 2026 USD ($)	Sep. 30, 2025 USD ($)	Feb. 28, 2027 USD ($)	Dec. 31, 2025 USD ($)	Jan. 20, 2023 ft²
Lessee Lease Description [Line Items]
Incremental borrowing rate for purposes of calculation of lease liabilities							11.50%		11.50%
Change in incremental borrowing rate									1.00%
Rent payment							$ 9,196		$ 9,196
Operating lease liability							7,600		7,600			$ 8,200
Operating lease right-of-use asset							6,082		6,082			$ 6,461
Operating lease expense							700	$ 800	2,000	$ 2,600
Receive rent payment							$ 4,310		$ 4,310
Bridgewater
Lessee Lease Description [Line Items]
Lease commencement date						Aug. 15, 2019
Lease agreement term				7 years 6 months		11 years
Number of renewal options \| RenewalOption						2
Lease renewal term						5 years
Description of lease agreement									will have a one-time option to terminate the agreement effective on the first day of the 97th month after the Commencement Date upon advance written notice and a termination payment specified in the Lease.
Lease termination description									one-time option to terminate the agreement effective on the first day of the 97th month after the Commencement Date
Lease termination existence of option to extend						true
Rent payment						$ 100
Area under sub-lease agreement \| ft²													50,000
Lease agreement area \| ft²													67,747
Sublease commencement date				Feb. 01, 2023
Receive rent payment				$ 100
Zug Switzerland
Lessee Lease Description [Line Items]
Lease commencement date					Feb. 01, 2022
Lease agreement term					5 years
Number of renewal options \| RenewalOption					1
Lease renewal term					5 years
Rent payment					$ 200
Lease termination date					Dec. 31, 2025
Dublin
Lessee Lease Description [Line Items]
Lease commencement date		Mar. 01, 2025	Sep. 01, 2024
Lease agreement term		2 years	2 years
Lease annual rent paid		$ 900	$ 500								$ 1,000
Operating lease commencement start date	Feb. 28, 2027
Operating lease commencement end date	Feb. 28, 2028	Feb. 28, 2027
Lease termination date			Feb. 28, 2025
Maximum
Lessee Lease Description [Line Items]
Short term lease period									12 months
Maximum \| Automobiles
Lessee Lease Description [Line Items]
Lease agreement term							36 months		36 months