| Cover | 12 Months Ended |
| Dec. 31, 2022 | |
| Document Information [Line Items] | |
| Document Type | PREC14A |
| Amendment Flag | false |
| Entity Information [Line Items] | |
| Entity Registrant Name | Alkermes plc. |
| Entity Central Index Key | 0001520262 |
| Pay vs Performance Disclosure - USD ($) | 12 Months Ended | ||
| Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | |
| Pay vs Performance Disclosure [Table] | |||
| Pay vs Performance [Table Text Block] | The amounts set forth below under the headings “Compensation Actually Paid to PEO” and “Average Compensation Actually Paid to Non-PEO NEOs” have been calculated in a manner consistent with Item 402(v) of Regulation S-K. Use of the term “compensation actually paid” is required by the SEC’s rules and, as a result of the calculation methodology required by the SEC, such amounts differ from compensation actually earned, realized or received by the individuals and the compensation decisions described in our Compensation Discussion and Analysis Summary Compensation Average Summary Compensation Average Compensation Actually Value of Initial Fixed $100 Investment Based on: (3) Year Compensation Table Total for PEO (1) ($) Actually Paid to PEO (1)(2) ($) Table Total for Non-PEO NEOs (1) ($) Paid to Non-PEO NEOs (1)(2) ($) TSR ($) Peer Group TSR ($) GAAP Net Income (Loss) ($ Millions) Non-GAAP Net Income (4) ($ Millions) (a) (b) (c) (d) (e) (f) (g) (h) (i) 2022 10,314,172 8,321,591 4,155,421 4,206,760 128.09 113.65 (158.3 ) 57.9 2021 8,846,588 11,225,263 2,942,671 2,882,217 114.02 126.45 (48.2 ) 129.1 2020 8,041,702 6,883,292 2,882,616 2,656,656 97.79 126.42 (110.9 ) 68.6 (1) Richard F. Pops 2020 2021 2022 James M. Frates Iain M. Brown Iain M. Brown David J. Gaffin James M. Frates David J. Gaffin Craig C. Hopkinson, M.D. David J. Gaffin Craig C. Hopkinson, M.D. Michael J. Landine Craig C. Hopkinson, M.D. Blair C. Jackson Blair C. Jackson (2) The amounts shown reflect the exclusion and inclusion of those certain amounts for the PEO and the non-PEO NEOs shown in the following tables. Equity values are calculated in accordance with FASB ASC Topic 718. Amounts shown in each of the Exclusion of Stock Awards and Option Awards columns are equal to the total amounts from the Stock Awards and Option Awards columns set forth in the Summary Compensation Table on page 118 of this proxy statement. Year Summary Compensation Table Total for PEO ($) Exclusion of Stock Awards and Option Awards for PEO ($) Inclusion of Equity Values for PEO ($) Compensation Actually Paid to PEO ($) 2022 10,314,172 (8,009,660 ) 6,017,079 8,321,591 2021 8,846,588 (6,564,945 ) 8,943,620 11,225,263 2020 8,041,702 (6,040,835 ) 4,882,425 6,883,292 Year Average Summary Compensation Table Total for Non-PEO NEOs ($) Average Exclusion of Stock Awards and Option Awards for Non-PEO NEOs ($) Average Inclusion of Equity Values for Non-PEO NEOs ($) Average Compensation Actually Paid to Non-PEO NEOs ($) 2022 4,155,421 (3,126,696 ) 3,178,035 4,206,760 2021 2,942,671 (2,141,519 ) 2,081,065 2,882,217 2020 2,882,616 (2,083,657 ) 1,857,697 2,656,656 The amounts shown in the Inclusion of Equity Values column in each of the above tables are derived from the following amounts: Year Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year for PEO ($) Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards for PEO ($) Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year for PEO ($) Fair Value at Last Day of Prior Year of Equity Awards Forfeited During Year for PEO ($) Total - Inclusion of Equity Values for PEO ($) 2022 6,635,906 (948,605 ) 329,778 — 6,017,079 2021 5,337,837 1,158,777 2,447,006 — 8,943,620 2020 5,747,325 (629,614 ) (235,286 ) — 4,882,425 Year Average Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year for Non-PEO NEOs ($) Average Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards for Non-PEO NEOs ($) Average Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year for Non-PEO NEOs ($) Average Fair Value at Last Day of Prior Year of Equity Awards Forfeited During Year for Non-PEO NEOs ($) Total - Average Inclusion of Equity Values for Non-PEO NEOs ($) 2022 2,930,046 137,112 110,877 — 3,178,035 2021 2,296,714 (439,567 ) 809,922 (586,004 ) 2,081,065 2020 2,010,019 (91,032 ) (61,290 ) — 1,857,697 (3) The peer group TSR shown in this table utilizes the Nasdaq Biotechnology Index, which we also utilize in the stock performance graph required by Item 201(e) of Regulation S-K included in our Annual Report. The comparison assumes $100 was invested in the Company and in the Nasdaq Biotechnology Index, respectively, for the period starting December 31, 2019 through the end of the year shown. Historical share price performance is not necessarily indicative of future share price performance. (4) We determined non-GAAP net income to be the most important financial performance measure used to link Company performance to compensation actually paid to our PEO and non-PEO NEOs in 2022. This financial performance measure may not have been the most important financial performance measure for years 2021 and 2020 and we may determine a different financial performance measure to be the most important financial performance measure in future years. See Appendix B for information regarding this non-GAAP financial measure. | ||
| Company Selected Measure Name | Non-GAAP Net Income | ||
| Named Executive Officers, Footnote [Text Block] | (1) Richard F. Pops 2020 2021 2022 James M. Frates Iain M. Brown Iain M. Brown David J. Gaffin James M. Frates David J. Gaffin Craig C. Hopkinson, M.D. David J. Gaffin Craig C. Hopkinson, M.D. Michael J. Landine Craig C. Hopkinson, M.D. Blair C. Jackson Blair C. Jackson | ||
| PEO Total Compensation Amount | $ 10,314,172 | $ 8,846,588 | $ 8,041,702 |
| PEO Actually Paid Compensation Amount | $ 8,321,591 | 11,225,263 | 6,883,292 |
| Adjustment To PEO Compensation, Footnote [Text Block] | (2) The amounts shown reflect the exclusion and inclusion of those certain amounts for the PEO and the non-PEO NEOs shown in the following tables. Equity values are calculated in accordance with FASB ASC Topic 718. Amounts shown in each of the Exclusion of Stock Awards and Option Awards columns are equal to the total amounts from the Stock Awards and Option Awards columns set forth in the Summary Compensation Table on page 118 of this proxy statement. Year Summary Compensation Table Total for PEO ($) Exclusion of Stock Awards and Option Awards for PEO ($) Inclusion of Equity Values for PEO ($) Compensation Actually Paid to PEO ($) 2022 10,314,172 (8,009,660 ) 6,017,079 8,321,591 2021 8,846,588 (6,564,945 ) 8,943,620 11,225,263 2020 8,041,702 (6,040,835 ) 4,882,425 6,883,292 The amounts shown in the Inclusion of Equity Values column in each of the above tables are derived from the following amounts: Year Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year for PEO ($) Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards for PEO ($) Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year for PEO ($) Fair Value at Last Day of Prior Year of Equity Awards Forfeited During Year for PEO ($) Total - Inclusion of Equity Values for PEO ($) 2022 6,635,906 (948,605 ) 329,778 — 6,017,079 2021 5,337,837 1,158,777 2,447,006 — 8,943,620 2020 5,747,325 (629,614 ) (235,286 ) — 4,882,425 | ||
| Non-PEO NEO Average Total Compensation Amount | $ 4,155,421 | 2,942,671 | 2,882,616 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 4,206,760 | 2,882,217 | 2,656,656 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | (2) The amounts shown reflect the exclusion and inclusion of those certain amounts for the PEO and the non-PEO NEOs shown in the following tables. Equity values are calculated in accordance with FASB ASC Topic 718. Amounts shown in each of the Exclusion of Stock Awards and Option Awards columns are equal to the total amounts from the Stock Awards and Option Awards columns set forth in the Summary Compensation Table on page 118 of this proxy statement. Year Average Summary Compensation Table Total for Non-PEO NEOs ($) Average Exclusion of Stock Awards and Option Awards for Non-PEO NEOs ($) Average Inclusion of Equity Values for Non-PEO NEOs ($) Average Compensation Actually Paid to Non-PEO NEOs ($) 2022 4,155,421 (3,126,696 ) 3,178,035 4,206,760 2021 2,942,671 (2,141,519 ) 2,081,065 2,882,217 2020 2,882,616 (2,083,657 ) 1,857,697 2,656,656 The amounts shown in the Inclusion of Equity Values column in each of the above tables are derived from the following amounts: Year Average Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year for Non-PEO NEOs ($) Average Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards for Non-PEO NEOs ($) Average Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year for Non-PEO NEOs ($) Average Fair Value at Last Day of Prior Year of Equity Awards Forfeited During Year for Non-PEO NEOs ($) Total - Average Inclusion of Equity Values for Non-PEO NEOs ($) 2022 2,930,046 137,112 110,877 — 3,178,035 2021 2,296,714 (439,567 ) 809,922 (586,004 ) 2,081,065 2020 2,010,019 (91,032 ) (61,290 ) — 1,857,697 | ||
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | |||
| Compensation Actually Paid vs. Net Income [Text Block] | |||
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | |||
| Total Shareholder Return Vs Peer Group [Text Block] | (3) The peer group TSR shown in this table utilizes the Nasdaq Biotechnology Index, which we also utilize in the stock performance graph required by Item 201(e) of Regulation S-K included in our Annual Report. The comparison assumes $100 was invested in the Company and in the Nasdaq Biotechnology Index, respectively, for the period starting December 31, 2019 through the end of the year shown. Historical share price performance is not necessarily indicative of future share price performance. | ||
| Tabular List [Table Text Block] | The most important financial performance measures used to link compensation actually paid to our NEOs for 2022 to Company performance are set forth below. For further information regarding these performance metrics and their function in our executive compensation program, see our Compensation Discussion and Analysis Proprietary Product Net Sales Relative Total Shareholder Return Non-GAAP Net Income* Non-GAAP Net Income* as a Percentage of Total Revenue * See Appendix B | ||
| Total Shareholder Return Amount | $ 128.09 | 114.02 | 97.79 |
| Peer Group Total Shareholder Return Amount | 113.65 | 126.45 | 126.42 |
| Net Income (Loss) | $ (158,300,000) | $ (48,200,000) | $ (110,900,000) |
| Company Selected Measure Amount | 57,900,000 | 129,100,000 | 68,600,000 |
| PEO Name | Richard F. Pops | Richard F. Pops | Richard F. Pops |
| Measure [Axis]: 1 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Proprietary Product Net Sales | ||
| Measure [Axis]: 2 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Relative Total Shareholder Return | ||
| Measure [Axis]: 3 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Non-GAAP Net Income | ||
| Non-GAAP Measure Description [Text Block] | (4) We determined non-GAAP net income to be the most important financial performance measure used to link Company performance to compensation actually paid to our PEO and non-PEO NEOs in 2022. This financial performance measure may not have been the most important financial performance measure for years 2021 and 2020 and we may determine a different financial performance measure to be the most important financial performance measure in future years. See Appendix B for information regarding this non-GAAP financial measure. | ||
| Measure [Axis]: 4 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Non-GAAP Net Income* as a Percentage of Total Revenue | ||
| PEO [Member] | Exclusion of Stock Awards and Option Awards | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ (8,009,660) | $ (6,564,945) | $ (6,040,835) |
| PEO [Member] | Inclusion of Equity Values | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 6,017,079 | 8,943,620 | 4,882,425 |
| PEO [Member] | Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 6,635,906 | 5,337,837 | 5,747,325 |
| PEO [Member] | Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (948,605) | 1,158,777 | (629,614) |
| PEO [Member] | Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 329,778 | 2,447,006 | (235,286) |
| Non-PEO NEO [Member] | Average Exclusion of Stock Awards and Option Awards | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (3,126,696) | (2,141,519) | (2,083,657) |
| Non-PEO NEO [Member] | Average Inclusion of Equity Values | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 3,178,035 | 2,081,065 | 1,857,697 |
| Non-PEO NEO [Member] | Average Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 2,930,046 | 2,296,714 | 2,010,019 |
| Non-PEO NEO [Member] | Average Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 137,112 | (439,567) | (91,032) |
| Non-PEO NEO [Member] | Average Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ 110,877 | 809,922 | $ (61,290) |
| Non-PEO NEO [Member] | Average Fair Value at Last Day of Prior Year of Equity Awards Forfeited During Year | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ (586,004) | ||
