Commitments and Contingent Liabilities	6 Months Ended
Jun. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	15. 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 June 30, 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 In January 2018 and in August 2019, Janssen Pharmaceuticals NV and Janssen Pharmaceuticals, Inc. initiated patent infringement lawsuits in the U.S. District Court for the District of New Jersey against Teva entities (Teva Pharmaceuticals USA, Inc. (“Teva”) and Teva Pharmaceuticals Industries, Ltd. (“Teva PI”)) and Mylan entities (Mylan Laboratories Limited (“Mylan Labs”), Mylan Pharmaceuticals Inc. (“Mylan”), and Mylan Institutional LLC), respectively, following filings by each of Teva and Mylan Labs of an abbreviated new drug application (“ANDA”) seeking approval to market a generic version of INVEGA SUSTENNA before the expiration of U.S. Patent No. 9,439,906. Requested judicial remedies in each of the lawsuits included recovery of litigation costs and injunctive relief. The Company is not a party to either of these proceedings. 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. 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 Litigation The Company has been named in two product liability lawsuits incidental to its normal business activities involving allegations that the FDA-approved VIVITROL labelling was inadequate and caused the users of the product to suffer from an opioid overdose and death. The Company believes the approved labelling was appropriate and intends to vigorously defend the cases.

Commitments and Contingent Liabilities

6 Months Ended

Jun. 30, 2020

Commitments And Contingencies Disclosure [Abstract]

15. 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 June 30, 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

In January 2018 and in August 2019, Janssen Pharmaceuticals NV and Janssen Pharmaceuticals, Inc. initiated patent infringement lawsuits in the U.S. District Court for the District of New Jersey against Teva entities (Teva Pharmaceuticals USA, Inc. (“Teva”) and Teva Pharmaceuticals Industries, Ltd. (“Teva PI”)) and Mylan entities (Mylan Laboratories Limited (“Mylan Labs”), Mylan Pharmaceuticals Inc. (“Mylan”), and Mylan Institutional LLC), respectively, following filings by each of Teva and Mylan Labs of an abbreviated new drug application (“ANDA”) seeking approval to market a generic version of INVEGA SUSTENNA before the expiration of U.S. Patent No. 9,439,906. Requested judicial remedies in each of the lawsuits included recovery of litigation costs and injunctive relief. The Company is not a party to either of these proceedings.

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.

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 Litigation

The Company has been named in two product liability lawsuits incidental to its normal business activities involving allegations that the FDA-approved VIVITROL labelling was inadequate and caused the users of the product to suffer from an opioid overdose and death. The Company believes the approved labelling was appropriate and intends to vigorously defend the cases.