Document and Entity Information - shares |
9 Months Ended | |
|---|---|---|
Sep. 30, 2016 |
Oct. 24, 2016 |
|
| Document and Entity Information | ||
| Entity Registrant Name | Alkermes plc. | |
| Entity Central Index Key | 0001520262 | |
| Document Type | 10-Q | |
| Document Period End Date | Sep. 30, 2016 | |
| Amendment Flag | false | |
| Current Fiscal Year End Date | --12-31 | |
| Entity Current Reporting Status | Yes | |
| Entity Filer Category | Large Accelerated Filer | |
| Entity Common Stock, Shares Outstanding | 151,970,482 | |
| Document Fiscal Year Focus | 2016 | |
| Document Fiscal Period Focus | Q3 |