    <SEC-DOCUMENT>0000950170-25-099629-index.html : 20250729
    <SEC-HEADER>0000950170-25-099629.hdr.sgml : 20250729
    <ACCEPTANCE-DATETIME>20250729160929
    ACCESSION NUMBER:		0000950170-25-099629
    CONFORMED SUBMISSION TYPE:	S-8
    PUBLIC DOCUMENT COUNT:		17
    FILED AS OF DATE:		20250729
    DATE AS OF CHANGE:		20250729
    EFFECTIVENESS DATE:		20250729

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			Alkermes plc.
    		CENTRAL INDEX KEY:			0001520262
    		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
    		ORGANIZATION NAME:           	03 Life Sciences
    		EIN:				981007018
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		S-8
    		SEC ACT:		1933 Act
    		SEC FILE NUMBER:	333-289037
    		FILM NUMBER:		251161929

    	BUSINESS ADDRESS:
    		STREET 1:		CONNAUGHT HOUSE
    		STREET 2:		1 BURLINGTON ROAD
    		CITY:			DUBLIN 4
    		STATE:			L2
    		ZIP:			00000
    		BUSINESS PHONE:		00-353-1-772-8000

    	MAIL ADDRESS:
    		STREET 1:		CONNAUGHT HOUSE
    		STREET 2:		1 BURLINGTON ROAD
    		CITY:			DUBLIN 4
    		STATE:			L2
    		ZIP:			00000

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	ANTLER SCIENCE TWO PLC
    		DATE OF NAME CHANGE:	20110804

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	Antler Science Two Ltd
    		DATE OF NAME CHANGE:	20110509
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>S-8
    <SEQUENCE>1
    <FILENAME>alks-20250729.htm
    <DESCRIPTION>S-8
    <TEXT>
    Document 1 - file: alks-20250729.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-5.1
    <SEQUENCE>2
    <FILENAME>alks-ex5_1.htm
    <DESCRIPTION>EX-5.1
    <TEXT>
    Document 2 - file: alks-ex5_1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-23.1
    <SEQUENCE>3
    <FILENAME>alks-ex23_1.htm
    <DESCRIPTION>EX-23.1
    <TEXT>
    Document 3 - file: alks-ex23_1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-FILING FEES
    <SEQUENCE>4
    <FILENAME>alks-exfiling_fees.htm
    <DESCRIPTION>EX-FILING FEES
    <TEXT>
    Document 4 - file: alks-exfiling_fees.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>img139586189_0.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 5 - file: img139586189_0.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>6
    <FILENAME>img139586189_1.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 6 - file: img139586189_1.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>7
    <FILENAME>img139586189_2.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 7 - file: img139586189_2.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>9
    <FILENAME>R1.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 9 - file: R1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>10
    <FILENAME>R2.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 10 - file: R2.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>11
    <FILENAME>R3.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 11 - file: R3.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>12
    <FILENAME>Show.js
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 12 - file: Show.js

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>13
    <FILENAME>report.css
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 13 - file: report.css

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>15
    <FILENAME>FilingSummary.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 15 - file: FilingSummary.html

    Document 15 - RAW XML: FilingSummary.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>JSON
    <SEQUENCE>17
    <FILENAME>MetaLinks.json
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 17 - file: MetaLinks.json

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>ZIP
    <SEQUENCE>18
    <FILENAME>0000950170-25-099629-xbrl.zip
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 18 - file: 0000950170-25-099629-xbrl.zip

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>19
    <FILENAME>alks-exfiling_fees_htm.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 19 - file: alks-exfiling_fees_htm.html

    Document 19 - RAW XML: alks-exfiling_fees_htm.xml

    </DOCUMENT>
    </SEC-DOCUMENT>