Collaborative Arrangements - Additional Information (Details)	12 Months Ended
Dec. 31, 2024 USD ($) Agreement
VUMERITY
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Percentage of net sales in royalty payment	15.00%
License agreement \| Janssen \| 9 O-H Risperidone Palimate [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Patent royalty rate (as a percent)	1.50%
Know-how royalty rate resets (as a percent)	3.50%
Period after the date of the first commercial sale of the product for license expiration	15 years
License agreement \| Janssen \| 9 O-H Risperidone Palimate [Member] \| Net sales of below $250.0 million
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Know-how royalty rate (as a percent)	3.50%
License agreement \| Janssen \| 9 O-H Risperidone Palimate [Member] \| Net sales between $250.0 million and 500.0 million
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Know-how royalty rate (as a percent)	5.50%
License agreement \| Janssen \| 9 O-H Risperidone Palimate [Member] \| Net sales greater than $500.0 million
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Know-how royalty rate (as a percent)	7.50%
License agreement \| Janssen \| 9 O-H Risperidone Palimate [Member] \| Minimum \| Net sales between $250.0 million and 500.0 million
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate worldwide net sales	$ 250,000,000
License agreement \| Janssen \| 9 O-H Risperidone Palimate [Member] \| Minimum \| Net sales greater than $500.0 million
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate worldwide net sales	500,000,000
License agreement \| Janssen \| 9 O-H Risperidone Palimate [Member] \| Maximum \| Net sales of below $250.0 million
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate worldwide net sales	250,000,000
License agreement \| Janssen \| 9 O-H Risperidone Palimate [Member] \| Maximum \| Net sales between $250.0 million and 500.0 million
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate worldwide net sales	$ 500,000,000
License agreement \| Janssen \| RISPERDAL CONSTA
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Royalty rate (as a percent)	2.50%
Period after the date of the first commercial sale of the product for license expiration	15 years
Number of license agreements \| Agreement	2
Notice period required to be given before termination of agreement	30 days
Period for resolving default or breach after the receipt of notice for termination of agreement	90 days
Manufacturing and supply agreement \| Janssen \| RISPERDAL CONSTA
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Period after the date of the first commercial sale of the product for license expiration	60 days
Notice period required to be given before termination of agreement	6 months
Manufacturing and supply agreement \| Janssen \| RISPERDAL CONSTA \| Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Royalty rate (as a percent)	7.50%
Royalty rate upon termination of manufacturing and supply agreement (as a percent)	2.50%
Manufacturing and supply agreement \| Janssen \| RISPERDAL CONSTA \| Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Royalty rate upon termination of manufacturing and supply agreement (as a percent)	5.00%

Represents the notice period required to be served before the termination of the agreement.

No definition available.

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- Definition

Represents the know-how patent royalty as a percentage of net sales under the collaborative agreements.

+ References

No definition available.

+ Details

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- Definition

Collaborative arrangement know how royalty rate resets.

+ References

No definition available.

+ Details

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- Definition

Represents the aggregate worldwide net sales tied to know-how royalty under the collaborative agreements.

+ References

No definition available.

+ Details

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- Definition

Represents the patent royalty as a percentage of net sales under the collaborative agreements.

+ References

No definition available.

+ Details

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

- Definition

Represents the period after the date of the first commercial sale of the product in a particular country that the agreement will expire.

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
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- Definition

Represents the period for resolving default or breach after the receipt of notice for termination of agreement.

+ References

No definition available.

+ Details

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- Definition

Represents royalty as a percentage of net sales under the collaborative agreements.

+ References

No definition available.

+ Details

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Namespace Prefix:	alks_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents royalty rate upon termination of related agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	alks_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of license agreements.

+ References

No definition available.

+ Details

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Namespace Prefix:	alks_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of net sales in royalty payment.

+ References

No definition available.

+ Details

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Namespace Prefix:	alks_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- 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/2003/role/disclosureRef
-Topic 808
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479402/808-10-50-1

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- Details

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- Details

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- Details

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- Details

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