Share-based compensation arrangement accounting modification charge.

No definition available.

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Namespace Prefix:	alks_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Amount of cost capitalized for award under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(ii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- 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

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
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- Definition

An excess of the fair value of the modified award over the fair value of the award immediately before the modification.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(2)(iii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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Period Type:

Share-based Compensation - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Feb. 29, 2024	Mar. 31, 2025	Dec. 31, 2024
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation cost capitalized		$ 3.2	$ 3.1
Share-based compensation, accounting modification charge	$ 6.8
Performance-based RSUs Awards
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Incremental share-based compensation expense due to achievement of performance criteria	$ 2.6