Commitments and Contingent Liabilities	12 Months Ended
Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	19. COMMITMENTS AND CONTINGENT LIABILITIES Litigation From time to time, the Company may be subject to legal proceedings and claims in the ordinary course of business. On a quarterly basis, the Company reviews the status of each significant matter and assesses its potential financial exposure. If the potential loss from any claim, asserted or unasserted, or legal proceeding is considered probable and the amount can be reasonably estimated, the Company would accrue a liability for the estimated loss. Because of uncertainties related to claims and litigation, accruals are based on the Company’s best estimates, utilizing all available information. On a periodic basis, as additional information becomes available, or based on specific events such as the outcome of litigation or settlement of claims, the Company may reassess the potential liability related to these matters and may revise these estimates, which could result in material adverse adjustments to the Company’s operating results. At December 31, 2020, there were no potential material losses from claims, asserted or unasserted, or legal proceedings that the Company determined were probable of occurring. INVEGA SUSTENNA ANDA Litigation Janssen Pharmaceuticals NV and Janssen Pharmaceuticals, Inc. initiated patent infringement lawsuits in the U.S. District Court for the District of New Jersey (the “NJ District Court”) in January 2018 against Teva Pharmaceuticals USA, Inc. (“Teva”) and Teva Pharmaceuticals Industries, Ltd. (“Teva PI”), in August 2019 against Mylan Laboratories Limited (“Mylan Labs”), Mylan Pharmaceuticals Inc. (“Mylan”), and Mylan Institutional LLC and in December 2019 against Pharmascience, Inc. (“Pharmascience”), Mallinckrodt plc, and SpecGX LLC, following the respective filings by each of Teva, Mylan Labs, and Pharmascience of an Abbreviated New Drug Application (“ANDA”) seeking approval from the FDA to market a generic version of INVEGA SUSTENNA before the expiration of U.S. Patent No. 9,439,906. In October 2020, a trial was held in the lawsuit between the Janssen entities and the Teva entities. Requested judicial remedies in each of the lawsuits included recovery of litigation costs and injunctive relief. The Company is not a party to any of these proceedings. INVEGA TRINZA ANDA Litigation In September 2020, Janssen Pharmaceuticals NV, Janssen Pharmaceuticals, Inc., and Janssen Research & Development, LLC, initiated a patent infringement lawsuit in the NJ District Court against Mylan Labs, Mylan, and Mylan Institutional LLC following the filing by Mylan Labs of an ANDA seeking approval from the FDA to market a generic version of INVEGA TRINZA before the expiration of U.S. Patent No. 10,143,693. Requested judicial remedies include recovery of litigation costs and injunctive relief. The Company is not a party to this proceeding. RISPERDAL CONSTA European Opposition Proceedings In December 2016, Nanjing Luye Pharmaceutical Co., Ltd., Pharmathen SA, Teva PI and Dehns Ltd (a law firm representing an unidentified opponent) filed notices of opposition with the European Patent Office (the “EPO”) in respect of EP 2 269 577 B (the “EP ’577 Patent”), which is a patent directed to certain risperidone microsphere compositions, including RISPERDAL CONSTA. Following a hearing on the matter in January 2019, the EPO issued a written decision revoking the EP’577 Patent in April 2019. The Company filed a notice of appeal of the decision to the EPO’s Technical Boards of Appeal in June 2019. Pharmathen SA submitted a reply on November 5, 2019 and Nanjing Luye Pharmaceutical Co Ltd. and Teva Pharmaceutical Industries Ltd. submitted replies on December 20, 2019. The Company will continue to vigorously defend the EP ’577 Patent. VIVITROL ANDA Litigation In September 2020, Alkermes, Inc. and Alkermes Pharma Ireland Limited filed a patent infringement lawsuit in the NJ District Court against Teva and Teva PI following the filing by Teva of an ANDA seeking approval from the FDA to engage in the commercial manufacture, use or sale of a generic version of VIVITROL (naltrexone for extended-release injectable suspension) before the expiration of the Company’s U.S. Patent No. 7,919,499. Teva filed its Answer on November 16, 2020, which included counterclaims against the Company. The Company filed its Reply to Teva’s counterclaims on December 7, 2020. The Company intends to vigorously defend its intellectual property. The filing of the lawsuit triggered a stay of FDA approval of the ANDA for up to 30 months in accordance with the U.S. Drug Price Competition and Patent Term Restoration Act of 1984 (the Hatch-Waxman Act). Government Matters The Company has received a subpoena and civil investigative demands from U.S. state and Federal governmental authorities for documents related to VIVITROL. The Company is cooperating with the investigations. Securities Litigation In December 2018 and January 2019, purported stockholders of the Company filed putative class actions against the Company and certain of its officers in the U.S. District Court for the Eastern District of New York (the “EDNY District Court”) captioned Karimian v. Alkermes plc, et al., No. 1:18-cv-07410 and McDermott v. Alkermes plc, et al., No. 1:19-cv-00624, respectively. In March 2019, the EDNY District Court consolidated the two cases and appointed a lead plaintiff. The plaintiff filed an amended complaint on July 9, 2019 naming one additional officer of the Company and one former officer of the Company as defendants. The amended complaint was filed on behalf of a putative class of purchasers of Alkermes securities during the period of July 31, 2014 through November 1, 2018 and alleges violations of Sections 10(b) and 20(a) of the Exchange Act based on allegedly false or misleading statements and omissions regarding the Company’s clinical methodologies and regulatory submission for ALKS 5461 and the FDA’s review and consideration of that submission. The lawsuit seeks, among other things, unspecified money damages, prejudgment and postjudgment interest, reasonable attorneys’ fees, expert fees and other costs. In August 2019, the defendants filed a pre-motion letter (in respect of a requested motion to dismiss filing) with the EDNY District Court and plaintiff filed a response. On November 27, 2019, the defendants served the plaintiff with a motion to dismiss, and on December 27, 2019, the plaintiff served the defendants with its opposition to such motion. On January 17, 2020, the defendants filed the fully-briefed motion, including a reply to the plaintiff’s opposition, with the EDNY District Court. Product Liability and Other Legal Proceedings The Company is also involved in product liability cases and other legal proceedings incidental to its normal business activities, including product liability cases alleging that the FDA-approved VIVITROL labeling was inadequate and caused the users of the product to suffer from opioid overdose and death. The Company intends to vigorously defend itself in these matters. While the outcome of any of these proceedings cannot be accurately predicted, the Company does not believe the ultimate resolution of any of these existing matters would have a material adverse effect on the Company’s business or financial condition. Purchase Commitments The Company has open purchase orders for plant and equipment as part of the normal course of business. At December 31, 2020, the Company’s open purchase orders were $3.5 million for capital commitments.

Commitments and Contingent Liabilities

12 Months Ended

Dec. 31, 2020

Commitments And Contingencies Disclosure [Abstract]

19. COMMITMENTS AND CONTINGENT LIABILITIES

Litigation

From time to time, the Company may be subject to legal proceedings and claims in the ordinary course of business. On a quarterly basis, the Company reviews the status of each significant matter and assesses its potential financial exposure. If the potential loss from any claim, asserted or unasserted, or legal proceeding is considered probable and the amount can be reasonably estimated, the Company would accrue a liability for the estimated loss. Because of uncertainties related to claims and litigation, accruals are based on the Company’s best estimates, utilizing all available information. On a periodic basis, as additional information becomes available, or based on specific events such as the outcome of litigation or settlement of claims, the Company may reassess the potential liability related to these matters and may revise these estimates, which could result in material adverse adjustments to the Company’s operating results. At December 31, 2020, there were no potential material losses from claims, asserted or unasserted, or legal proceedings that the Company determined were probable of occurring.

INVEGA SUSTENNA ANDA Litigation

Janssen Pharmaceuticals NV and Janssen Pharmaceuticals, Inc. initiated patent infringement lawsuits in the U.S. District Court for the District of New Jersey (the “NJ District Court”) in January 2018 against Teva Pharmaceuticals USA, Inc. (“Teva”) and Teva Pharmaceuticals Industries, Ltd. (“Teva PI”), in August 2019 against Mylan Laboratories Limited (“Mylan Labs”), Mylan Pharmaceuticals Inc. (“Mylan”), and Mylan Institutional LLC and in December 2019 against Pharmascience, Inc. (“Pharmascience”), Mallinckrodt plc, and SpecGX LLC, following the respective filings by each of Teva, Mylan Labs, and Pharmascience of an Abbreviated New Drug Application (“ANDA”) seeking approval from the FDA to market a generic version of INVEGA SUSTENNA before the expiration of U.S. Patent No. 9,439,906. In October 2020, a trial was held in the lawsuit between the Janssen entities and the Teva entities. Requested judicial remedies in each of the lawsuits included recovery of litigation costs and injunctive relief. The Company is not a party to any of these proceedings.

INVEGA TRINZA ANDA Litigation

In September 2020, Janssen Pharmaceuticals NV, Janssen Pharmaceuticals, Inc., and Janssen Research & Development, LLC, initiated a patent infringement lawsuit in the NJ District Court against Mylan Labs, Mylan, and Mylan Institutional LLC following the filing by Mylan Labs of an ANDA seeking approval from the FDA to market a generic version of INVEGA TRINZA before the expiration of U.S. Patent No. 10,143,693. Requested judicial remedies include recovery of litigation costs and injunctive relief. The Company is not a party to this proceeding.

RISPERDAL CONSTA European Opposition Proceedings

In December 2016, Nanjing Luye Pharmaceutical Co., Ltd., Pharmathen SA, Teva PI and Dehns Ltd (a law firm representing an unidentified opponent) filed notices of opposition with the European Patent Office (the “EPO”) in respect of EP 2 269 577 B (the “EP ’577 Patent”), which is a patent directed to certain risperidone microsphere compositions, including RISPERDAL CONSTA. Following a hearing on the matter in January 2019, the EPO issued a written decision revoking the EP’577 Patent in April 2019. The Company filed a notice of appeal of the decision to the EPO’s Technical Boards of Appeal in June 2019. Pharmathen SA submitted a reply on November 5, 2019 and Nanjing Luye Pharmaceutical Co Ltd. and Teva Pharmaceutical Industries Ltd. submitted replies on December 20, 2019. The Company will continue to vigorously defend the EP ’577 Patent.

VIVITROL ANDA Litigation

In September 2020, Alkermes, Inc. and Alkermes Pharma Ireland Limited filed a patent infringement lawsuit in the NJ District Court against Teva and Teva PI following the filing by Teva of an ANDA seeking approval from the FDA to engage in the commercial manufacture, use or sale of a generic version of VIVITROL (naltrexone for extended-release injectable suspension) before the expiration of the Company’s U.S. Patent No. 7,919,499. Teva filed its Answer on November 16, 2020, which included counterclaims against the Company. The Company filed its Reply to Teva’s counterclaims on December 7, 2020. The Company intends to vigorously defend its intellectual property. The filing of the lawsuit triggered a stay of FDA approval of the ANDA for up to 30 months in accordance with the U.S. Drug Price Competition and Patent Term Restoration Act of 1984 (the Hatch-Waxman Act).

Government Matters

The Company has received a subpoena and civil investigative demands from U.S. state and Federal governmental authorities for documents related to VIVITROL. The Company is cooperating with the investigations.

Securities Litigation

In December 2018 and January 2019, purported stockholders of the Company filed putative class actions against the Company and certain of its officers in the U.S. District Court for the Eastern District of New York (the “EDNY District Court”) captioned Karimian v. Alkermes plc, et al., No. 1:18-cv-07410 and McDermott v. Alkermes plc, et al., No. 1:19-cv-00624, respectively. In March 2019, the EDNY District Court consolidated the two cases and appointed a lead plaintiff. The plaintiff filed an amended complaint on July 9, 2019 naming one additional officer of the Company and one former officer of the Company as defendants. The amended complaint was filed on behalf of a putative class of purchasers of Alkermes securities during the period of July 31, 2014 through November 1, 2018 and alleges violations of Sections 10(b) and 20(a) of the Exchange Act based on allegedly false or misleading statements and omissions regarding the Company’s clinical methodologies and regulatory submission for ALKS 5461 and the FDA’s review and consideration of that submission. The lawsuit seeks, among other things, unspecified money damages, prejudgment and postjudgment interest, reasonable attorneys’ fees, expert fees and other costs. In August 2019, the defendants filed a pre-motion letter (in respect of a requested motion to dismiss filing) with the EDNY District Court and plaintiff filed a response. On November 27, 2019, the defendants served the plaintiff with a motion to dismiss, and on December 27, 2019, the plaintiff served the defendants with its opposition to such motion. On January 17, 2020, the defendants filed the fully-briefed motion, including a reply to the plaintiff’s opposition, with the EDNY District Court.

Product Liability and Other Legal Proceedings

The Company is also involved in product liability cases and other legal proceedings incidental to its normal business activities, including product liability cases alleging that the FDA-approved VIVITROL labeling was inadequate and caused the users of the product to suffer from opioid overdose and death. The Company intends to vigorously defend itself in these matters. While the outcome of any of these proceedings cannot be accurately predicted, the Company does not believe the ultimate resolution of any of these existing matters would have a material adverse effect on the Company’s business or financial condition.

Purchase Commitments

The Company has open purchase orders for plant and equipment as part of the normal course of business. At December 31, 2020, the Company’s open purchase orders were $3.5 million for capital commitments.