Commitments and Contingencies	12 Months Ended
Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	(8) Commitments and Contingencies Litigation On February 22, 2019, a purported investor in our publicly traded securities filed a putative class action lawsuit against Amarin Corporation plc, our chief executive officer and chief scientific officer in the U.S. District Court for the District of New Jersey, Debendra Sharma v. Amarin Corporation plc, John F. Thero and Steven Ketchum, No. 2:19-cv-06601 (D.N.J. Feb. 22, 2019). On March 12, 2019, another purported investor filed a substantially similar lawsuit captioned Richard Borghesi v. Amarin Corporation plc, John F. Thero and Steven Ketchum, No. 3:19-cv-08423 (D.N.J. March 12, 2019). On May 14, 2019 the court consolidated the cases under the caption In re Amarin Corporation PLC Securities Litigation, No. 3:19-cv-06601 and appointed two other purported shareholders, Dan Kotecki and the Gaetano Cecchini Living Trust, as Co-Lead Plaintiffs. Co-Lead Plaintiffs filed a consolidated amended complaint, or Amended Complaint, on July 22, 2019 that adds as defendants our current chief medical officer and our former chief executive officer, who is a current director. The Amended Complaint alleges that from September 24, 2018 to November 9, 2018 the Company misled investors by releasing topline results for the REDUCE-IT study without disclosing data on biomarker increases in the placebo group as compared with baseline measurement. The Amended Complaint alleges that these data suggest that the mineral oil placebo used in the REDUCE-IT study may have interfered with statin absorption in the placebo group, which they allege may have increased adverse outcomes in the placebo group. The Amended Complaint further allege that these purported misrepresentations and omissions inflated our share price. Based on these allegations, the suit asserts claims under the Securities Exchange Act of 1934 and seeks unspecified monetary damages and attorneys’ fees and costs. The Company believes that it has valid defenses and will vigorously defend against the claims, but cannot predict the outcome. The Company is unable to reasonably estimate the loss exposure, if any, associated with these claims. The Company has insurance coverage that is anticipated to cover any significant loss exposure that may arise from this action after payment by the Company of the associated deductible obligation. On August 30, 2017, Amarin Pharma, Inc. and Amarin Pharmaceuticals Ireland Limited, each wholly-owned subsidiaries of Amarin Corporation plc, filed a lawsuit with the United States International Trade Commission, or the ITC, captioned In the Matter of Certain Synthetically Produced, Predominantly EPA Omega-3 Products in Ethyl Ester or Re-esterified Triglyceride Form, USITC Docket 337-3247, against manufacturers, importers, and distributors of products containing synthetically produced omega-3 products in ethyl ester or re-esterified triglyceride form that contain more EPA than DHA or any other single component for use in or as dietary supplements. The lawsuit sought an investigation by the ITC under Section 337 of the Tariff Act of 1930 (19 U.S.C. §1337), which makes unlawful unfair methods of competition and unfair acts involving the importation and sale of articles in the United States that injure or threaten injury to a domestic industry. On October 27, 2017, the ITC determined to not institute our requested investigation. On December 1, 2017, the Company appealed the ITC’s non-institution decision to the United States Court of Appeals for the Federal Circuit (Case Nos. 18-1247, 18-114). That appeal is ongoing. The Company intends to pursue this matter vigorously. In September and October 2016, the Company received paragraph IV certification notices from four companies contending to varying degrees that certain of its patents are invalid, unenforceable and/or will not be infringed by the manufacture, use, sale or offer for sale of a generic form of Vascepa as described in those companies’ abbreviated new drug applications, or ANDAs. The Company filed patent infringement lawsuits against three of these four ANDA applicants. In October 2016, Amarin filed a lawsuit against Roxane Laboratories, Inc. and related parties (collectively, “Roxane”) in the U.S. District Court for the District of Nevada. The case against Roxane is captioned Amarin Pharma, Inc. et al. v. Roxane Laboratories, Inc. et al., Civ. A. No. 2:16-cv-02525 (D. Nev.). According to a stipulation filed with the Nevada court, in December 2016, Roxane transferred its ANDA to West-Ward Pharmaceuticals International Limited, which then designated West-Ward Pharmaceuticals Corp. (or together with West-Ward Pharmaceuticals International Limited, West-Ward) as its agent for FDA communications. In view of the ANDA transfer, in February 2017, West-Ward replaced Roxane and related parties as Defendants in the above-referenced case. The case against West-Ward is now captioned Amarin Pharma, Inc. et al. v. West-Ward Pharmaceuticals Corp. et al., Civ. A. No. 2:16-cv-02525 (D. Nev.). In November 2016, Amarin filed a lawsuit against Dr. Reddy’s Laboratories, Inc. and Dr. Reddy’s Laboratories, Ltd. (collectively, “DRL”) in the U.S. District Court for the District of Nevada. The case against DRL is captioned Amarin Pharma, Inc. et al. v. Dr. Reddy’s Laboratories, Inc. et al., Civ. A. No. 2:16-cv-02562 (D. Nev.). In November 2016, Amarin filed a lawsuit against Teva Pharmaceuticals USA, Inc. and Teva Pharmaceuticals Industries Limited (collectively, “Teva”) in the U.S. District Court for the District of Nevada. The case against Teva is captioned Amarin Pharma, Inc. et al. v. Teva Pharmaceuticals USA, Inc. et al., Civ. A. No. 2:16-cv-02658. In all three lawsuits, Amarin is seeking, among other remedies, an order enjoining each defendant from marketing generic versions of Vascepa before the last to expire of the asserted patents in 2030. The three lawsuits have been consolidated for pretrial proceedings. As a result of the statutory stay associated with the filing of these lawsuits under the Hatch-Waxman Act, the FDA cannot grant final approval to West-Ward, DRL, or Teva’s respective ANDA before January 2020, unless there is an earlier court decision holding that the subject patents are not infringed and/or are invalid. The fourth ANDA applicant referenced above is Apotex Inc., or Apotex, which sent Amarin a paragraph IV certification notice in September 2016. The notice reflected that Apotex made a paragraph IV notice as to some, but not all, of the patents listed in the Orange Book for Vascepa. Because Apotex did not make a paragraph IV certification as to all listed patents, Apotex cannot market a generic version of Vascepa before the last to expire of the patents for which Apotex did not make a paragraph IV certification, which is in 2030. At a later date, Apotex may elect to amend its ANDA in order to make a paragraph IV certification as to additional listed patents. If and when Apotex does make such an amendment, it would be required to send Amarin an additional paragraph IV certification notice, and Amarin would then have the ability to file a lawsuit against Apotex pursuant to the Hatch-Waxman Act. In October 2016, the Company introduced to the market a 0.5-gram dose strength of Vascepa. In August 2017, as anticipated, the Company received a paragraph IV certification notice from Teva contending that certain of its patents are invalid, unenforceable and/or will not be infringed by the manufacture, use, sale or offer for sale of a generic form of the 0.5-gram dose strength of Vascepa, as described in the Teva ANDA. This Teva ANDA was filed as an amendment to the 1-gram Teva ANDA and is related to patents already at issue in the 1-gram Vascepa patent litigation. This certification followed the related listing in the Orange Book of patents associated with the 0.5-gram product in June 2017. This June 2017 listing was within the five-year, post NDA-approval period during which the Hatch-Waxman Amendments require a paragraph IV certification of patent invalidity or non-infringement under the Hatch-Waxman, five-year, NCE regulatory scheme. Accordingly, in October 2017, the Company filed a patent infringement lawsuit against Teva in the U.S. District Court for the District of Nevada. The case is captioned Amarin Pharma, Inc. et al. v. Teva Pharmaceuticals USA, Inc. et al., Civ. A. No. 2:17-cv-2641 (D. Nev.). In this lawsuit, the Company sought, among other remedies, an order enjoining Teva from marketing generic versions of the 0.5-gram dose strength of Vascepa before the last to expire of the asserted patents in 2030. On May 24, 2018, the Company entered into a settlement agreement with Teva that resolves its ANDA patent litigation as it relates to Teva’s as amended ANDA for both the 1-gram and 0.5-gram dose strengths of Vascepa. As part of this settlement agreement, Teva may first begin selling its generic version of Vascepa in the United States on August 9, 2029, or earlier under certain customary circumstances, including commercial launch by another generic manufacturer under certain circumstances, in which event Teva would pay the Company certain royalties on its generic Vascepa products. The ANDA patent litigation continues in the United States District Court for the District of Nevada with parties West-Ward and DRL. In July 2018, as anticipated, the Company received a paragraph IV certification notice from DRL contending that certain of its patents are invalid, unenforceable and/or will not be infringed by the manufacture, use, sale or offer for sale of a generic form of the 0.5-gram dose strength of Vascepa, as described in the DRL ANDA. This DRL ANDA was filed as an amendment to the 1-gram DRL ANADA and is related to patents already at issue in the 1-gram Vascepa patent litigation. This certification followed the related listing in the Orange Book of patents associated with the 0.5-gram product in June 2017. This June 2017 listing was within the five-year, post NDA-approval period during which the Hatch-Waxman Amendments require a paragraph IV certification of patent invalidity or non-infringement lawsuit against DRL in the U.S. District Court for the District of Nevada. The case is captioned Amarin Pharma, Inc. et al. v. Dr. Reddy’s Laboratories, Inc. et al., Civ. A. No. 2:18-cv-01596 (D. Nev.). In this lawsuit, the Company is seeking, among other remedies, an order enjoining DRL from marketing generic versions of the 0.5-gram dose strength of Vascepa before the last to expire of the asserted patents in 2030. In light of the overlap between the cases, DRL and Amarin have stipulated that the final judgment on the merits of the parties’ contentions in the consolidated 1-gram action shall also be binding in the 0.5-gram case. The Company intends to vigorously enforce its intellectual property rights relating to Vascepa, but cannot predict the outcome of these lawsuits or any subsequently filed lawsuits. In addition to the above, in the ordinary course of business, the Company is from time to time involved in lawsuits, claims, investigations, proceedings, and threats of litigation relating to intellectual property, commercial arrangements and other matters. Milestone and Supply Purchase Obligations The Company entered into long-term supply agreements with multiple FDA-approved API suppliers and encapsulators. Certain supply agreements require annual minimum volume commitments by the Company and certain volume shortfalls may require payments for such shortfalls. These agreements include requirements for the suppliers to meet certain product specifications and qualify their materials and facilities with applicable regulatory authorities including the FDA. The Company has incurred certain costs associated with the qualification of product produced by these suppliers. Pursuant to the supply agreements, there is a total of approximately $192.4 million that is potentially payable over the term of such agreements based on minimum purchase obligations. The Company continues to meet its contractual purchase obligations. Under the 2004 share repurchase agreement with Laxdale Limited, or Laxdale, upon receipt of marketing approval in Europe for the first indication for Vascepa (or first indication of any product containing Amarin Neuroscience Limited intellectual property acquired from Laxdale in 2004), the Company must make an aggregate stock or cash payment to the former shareholders of Laxdale (at the sole option of each of the sellers) of £7.5 million (approximately $9.9 million as of December 31, 2019). Also under the Laxdale agreement, upon receipt of a marketing approval in Europe for a further indication of Vascepa (or further indication of any other product using Amarin Neuroscience Limited intellectual property), the Company must make an aggregate stock or cash payment (at the sole option of each of the sellers) of £5 million (approximately $6.6 million as of December 31, 2019) for the potential market approval . The Company has no provision for any of the obligations above since the amounts are either not paid or payable as of December 31, 2019.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2019

Commitments And Contingencies Disclosure [Abstract]

(8) Commitments and Contingencies

Litigation

On February 22, 2019, a purported investor in our publicly traded securities filed a putative class action lawsuit against Amarin Corporation plc, our chief executive officer and chief scientific officer in the U.S. District Court for the District of New Jersey, Debendra Sharma v. Amarin Corporation plc, John F. Thero and Steven Ketchum, No. 2:19-cv-06601 (D.N.J. Feb. 22, 2019). On March 12, 2019, another purported investor filed a substantially similar lawsuit captioned Richard Borghesi v. Amarin Corporation plc, John F. Thero and Steven Ketchum, No. 3:19-cv-08423 (D.N.J. March 12, 2019). On May 14, 2019 the court consolidated the cases under the caption In re Amarin Corporation PLC Securities Litigation, No. 3:19-cv-06601 and appointed two other purported shareholders, Dan Kotecki and the Gaetano Cecchini Living Trust, as Co-Lead Plaintiffs.

Co-Lead Plaintiffs filed a consolidated amended complaint, or Amended Complaint, on July 22, 2019 that adds as defendants our current chief medical officer and our former chief executive officer, who is a current director. The Amended Complaint alleges that from September 24, 2018 to November 9, 2018 the Company misled investors by releasing topline results for the REDUCE-IT study without disclosing data on biomarker increases in the placebo group as compared with baseline measurement. The Amended Complaint alleges that these data suggest that the mineral oil placebo used in the REDUCE-IT study may have interfered with statin absorption in the placebo group, which they allege may have increased adverse outcomes in the placebo group. The Amended Complaint further allege that these purported misrepresentations and omissions inflated our share price. Based on these allegations, the suit asserts claims under the Securities Exchange Act of 1934 and seeks unspecified monetary damages and attorneys’ fees and costs.

The Company believes that it has valid defenses and will vigorously defend against the claims, but cannot predict the outcome. The Company is unable to reasonably estimate the loss exposure, if any, associated with these claims. The Company has insurance coverage that is anticipated to cover any significant loss exposure that may arise from this action after payment by the Company of the associated deductible obligation.

On August 30, 2017, Amarin Pharma, Inc. and Amarin Pharmaceuticals Ireland Limited, each wholly-owned subsidiaries of Amarin Corporation plc, filed a lawsuit with the United States International Trade Commission, or the ITC, captioned In the Matter of Certain Synthetically Produced, Predominantly EPA Omega-3 Products in Ethyl Ester or Re-esterified Triglyceride Form, USITC Docket 337-3247, against manufacturers, importers, and distributors of products containing synthetically produced omega-3 products in ethyl ester or re-esterified triglyceride form that contain more EPA than DHA or any other single component for use in or as dietary supplements. The lawsuit sought an investigation by the ITC under Section 337 of the Tariff Act of 1930 (19 U.S.C. §1337), which makes unlawful unfair methods of competition and unfair acts involving the importation and sale of articles in the United States that injure or threaten injury to a domestic industry. On October 27, 2017, the ITC determined to not institute our requested investigation. On December 1, 2017, the Company appealed the ITC’s non-institution decision to the United States Court of Appeals for the Federal Circuit (Case Nos. 18-1247, 18-114). That appeal is ongoing. The Company intends to pursue this matter vigorously.

In September and October 2016, the Company received paragraph IV certification notices from four companies contending to varying degrees that certain of its patents are invalid, unenforceable and/or will not be infringed by the manufacture, use, sale or offer for sale of a generic form of Vascepa as described in those companies’ abbreviated new drug applications, or ANDAs. The Company filed patent infringement lawsuits against three of these four ANDA applicants. In October 2016, Amarin filed a lawsuit against Roxane Laboratories, Inc. and related parties (collectively, “Roxane”) in the U.S. District Court for the District of Nevada. The case against Roxane is captioned Amarin Pharma, Inc. et al. v. Roxane Laboratories, Inc. et al., Civ. A. No. 2:16-cv-02525 (D. Nev.). According to a stipulation filed with the Nevada court, in December 2016, Roxane transferred its ANDA to West-Ward Pharmaceuticals International Limited, which then designated West-Ward Pharmaceuticals Corp. (or together with West-Ward Pharmaceuticals International Limited, West-Ward) as its agent for FDA communications. In view of the ANDA transfer, in February 2017, West-Ward replaced Roxane and related parties as Defendants in the above-referenced case. The case against West-Ward is now captioned Amarin Pharma, Inc. et al. v. West-Ward Pharmaceuticals Corp. et al., Civ. A. No. 2:16-cv-02525 (D. Nev.). In November 2016, Amarin filed a lawsuit against Dr. Reddy’s Laboratories, Inc. and Dr. Reddy’s Laboratories, Ltd. (collectively, “DRL”) in the U.S. District Court for the District of Nevada. The case against DRL is captioned Amarin Pharma, Inc. et al. v. Dr. Reddy’s Laboratories, Inc. et al., Civ. A. No. 2:16-cv-02562 (D. Nev.). In November 2016, Amarin filed a lawsuit against Teva Pharmaceuticals USA, Inc. and Teva Pharmaceuticals Industries Limited (collectively, “Teva”) in the U.S. District Court for the District of Nevada. The case against Teva is captioned Amarin Pharma, Inc. et al. v. Teva Pharmaceuticals USA, Inc. et al., Civ. A. No. 2:16-cv-02658. In all three lawsuits, Amarin is seeking, among other remedies, an order enjoining each defendant from marketing generic versions of Vascepa before the last to expire of the asserted patents in 2030. The three lawsuits have been consolidated for pretrial proceedings. As a result of the statutory stay associated with the filing of these lawsuits under the Hatch-Waxman Act, the FDA cannot grant final approval to West-Ward, DRL, or Teva’s respective ANDA before January 2020, unless there is an earlier court decision holding that the subject patents are not infringed and/or are invalid.

The fourth ANDA applicant referenced above is Apotex Inc., or Apotex, which sent Amarin a paragraph IV certification notice in September 2016. The notice reflected that Apotex made a paragraph IV notice as to some, but not all, of the patents listed in the Orange Book for Vascepa. Because Apotex did not make a paragraph IV certification as to all listed patents, Apotex cannot market a generic version of Vascepa before the last to expire of the patents for which Apotex did not make a paragraph IV certification, which is in 2030. At a later date, Apotex may elect to amend its ANDA in order to make a paragraph IV certification as to additional listed patents. If and when Apotex does make such an amendment, it would be required to send Amarin an additional paragraph IV certification notice, and Amarin would then have the ability to file a lawsuit against Apotex pursuant to the Hatch-Waxman Act.

In October 2016, the Company introduced to the market a 0.5-gram dose strength of Vascepa. In August 2017, as anticipated, the Company received a paragraph IV certification notice from Teva contending that certain of its patents are invalid, unenforceable and/or will not be infringed by the manufacture, use, sale or offer for sale of a generic form of the 0.5-gram dose strength of Vascepa, as described in the Teva ANDA. This Teva ANDA was filed as an amendment to the 1-gram Teva ANDA and is related to patents already at issue in the 1-gram Vascepa patent litigation. This certification followed the related listing in the Orange Book of patents associated with the 0.5-gram product in June 2017. This June 2017 listing was within the five-year, post NDA-approval period during which the Hatch-Waxman Amendments require a paragraph IV certification of patent invalidity or non-infringement under the Hatch-Waxman, five-year, NCE regulatory scheme. Accordingly, in October 2017, the Company filed a patent infringement lawsuit against Teva in the U.S. District Court for the District of Nevada. The case is captioned Amarin Pharma, Inc. et al. v. Teva Pharmaceuticals USA, Inc. et al., Civ. A. No. 2:17-cv-2641 (D. Nev.). In this lawsuit, the Company sought, among other remedies, an order enjoining Teva from marketing generic versions of the 0.5-gram dose strength of Vascepa before the last to expire of the asserted patents in 2030.

On May 24, 2018, the Company entered into a settlement agreement with Teva that resolves its ANDA patent litigation as it relates to Teva’s as amended ANDA for both the 1-gram and 0.5-gram dose strengths of Vascepa. As part of this settlement agreement, Teva may first begin selling its generic version of Vascepa in the United States on August 9, 2029, or earlier under certain customary circumstances, including commercial launch by another generic manufacturer under certain circumstances, in which event Teva would pay the Company certain royalties on its generic Vascepa products. The ANDA patent litigation continues in the United States District Court for the District of Nevada with parties West-Ward and DRL.

In July 2018, as anticipated, the Company received a paragraph IV certification notice from DRL contending that certain of its patents are invalid, unenforceable and/or will not be infringed by the manufacture, use, sale or offer for sale of a generic form of the 0.5-gram dose strength of Vascepa, as described in the DRL ANDA. This DRL ANDA was filed as an amendment to the 1-gram DRL ANADA and is related to patents already at issue in the 1-gram Vascepa patent litigation. This certification followed the related listing in the Orange Book of patents associated with the 0.5-gram product in June 2017. This June 2017 listing was within the five-year, post NDA-approval period during which the Hatch-Waxman Amendments require a paragraph IV certification of patent invalidity or non-infringement lawsuit against DRL in the U.S. District Court for the District of Nevada. The case is captioned Amarin Pharma, Inc. et al. v. Dr. Reddy’s Laboratories, Inc. et al., Civ. A. No. 2:18-cv-01596 (D. Nev.). In this lawsuit, the Company is seeking, among other remedies, an order enjoining DRL from marketing generic versions of the 0.5-gram dose strength of Vascepa before the last to expire of the asserted patents in 2030. In light of the overlap between the cases, DRL and Amarin have stipulated that the final judgment on the merits of the parties’ contentions in the consolidated 1-gram action shall also be binding in the 0.5-gram case.

The Company intends to vigorously enforce its intellectual property rights relating to Vascepa, but cannot predict the outcome of these lawsuits or any subsequently filed lawsuits.

In addition to the above, in the ordinary course of business, the Company is from time to time involved in lawsuits, claims, investigations, proceedings, and threats of litigation relating to intellectual property, commercial arrangements and other matters.

Milestone and Supply Purchase Obligations

The Company entered into long-term supply agreements with multiple FDA-approved API suppliers and encapsulators. Certain supply agreements require annual minimum volume commitments by the Company and certain volume shortfalls may require payments for such shortfalls.

These agreements include requirements for the suppliers to meet certain product specifications and qualify their materials and facilities with applicable regulatory authorities including the FDA. The Company has incurred certain costs associated with the qualification of product produced by these suppliers.

Pursuant to the supply agreements, there is a total of approximately $192.4 million that is potentially payable over the term of such agreements based on minimum purchase obligations. The Company continues to meet its contractual purchase obligations.

Under the 2004 share repurchase agreement with Laxdale Limited, or Laxdale, upon receipt of marketing approval in Europe for the first indication for Vascepa (or first indication of any product containing Amarin Neuroscience Limited intellectual property acquired from Laxdale in 2004), the Company must make an aggregate stock or cash payment to the former shareholders of Laxdale (at the sole option of each of the sellers) of £7.5 million (approximately $9.9 million as of December 31, 2019). Also under the Laxdale agreement, upon receipt of a marketing approval in Europe for a further indication of Vascepa (or further indication of any other product using Amarin Neuroscience Limited intellectual property), the Company must make an aggregate stock or cash payment (at the sole option of each of the sellers) of £5 million (approximately $6.6 million as of December 31, 2019) for the potential market approval .

The Company has no provision for any of the obligations above since the amounts are either not paid or payable as of December 31, 2019.