Document and Entity Information |
Feb. 24, 2026 |
|---|---|
| Cover [Abstract] | |
| Document Type | 8-K/A |
| Amendment Flag | true |
| Document Period End Date | Feb. 24, 2026 |
| Entity Registrant Name | Alkermes plc. |
| Entity Central Index Key | 0001520262 |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-35299 |
| Entity Incorporation, State or Country Code | L2 |
| Entity Tax Identification Number | 98-1007018 |
| Entity Address, Address Line One | Connaught House |
| Entity Address, Address Line Two | 1 Burlington Road |
| Entity Address, City or Town | Dublin 4 |
| Entity Address, Country | IE |
| Entity Address, Postal Zip Code | D04 C5Y6 |
| City Area Code | 353 |
| Local Phone Number | 1-772-8000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Ordinary shares, $0.01 par value |
| Trading Symbol | ALKS |
| Security Exchange Name | NASDAQ |
| Amendment Description | Alkermes plc (the “Company”) filed a Current Report on Form 8-K on February 25, 2026 (the “Original Form 8-K”), reporting, among other items, that the Company’s board of directors (the “Board”) had appointed Blair C. Jackson, the Company’s then-current Executive Vice President, Chief Operating Officer, to serve as the Company’s Chief Executive Officer (“CEO”), effective August 1, 2026. This Amendment No. 1 on Form 8-K/A (this “Form 8-K/A”) amends and supplements Item 5.02 of the Original Form 8-K to provide information regarding additional actions taken by the Board in connection with Mr. Jackson’s appointment, including (i) information regarding the compensation awarded to Mr. Jackson, which was not yet determined at the time of filing of the Original Form 8-K and therefore excluded from the Original Form 8-K in reliance on the instructions to Item 5.02, and (ii) Mr. Jackson’s appointment as a director of the Company, effective August 1, 2026. This Form 8-K/A does not amend any other item of the Original Form 8-K. |