Nature of Business and Basis of Presentation	12 Months Ended
Dec. 31, 2013
Nature of Business and Basis of Presentation	(1) Nature of Business and Basis of Presentation *Nature of Business* Amarin Corporation plc, “Amarin” or the “Company” is a biopharmaceutical company with expertise in lipid science focused on the commercialization and development of therapeutics to improve cardiovascular health. Our lead product, Vascepa^® (icosapent ethyl) capsules, is approved by the U.S. Food and Drug Administration, or FDA, for use as an adjunct to diet to reduce triglyceride levels in adult patients with severe (TG >500mg/dL) hypertriglyceridemia. The Company refers to this approved indication for Vascepa as the MARINE indication. The Company began marketing and selling Vascepa in the United States in January 2013. Vascepa is available in the United States by prescription only. The Company markets Vascepa through its sales force of approximately 150 sales professionals, including sales representatives and their managers. Triglycerides are fats in the blood. Hypertriglyceridemia refers to a condition in which patients have high levels of triglycerides in the bloodstream. It is estimated that over 40 million adults in the United States have elevated triglyceride levels (TG >200mg/dL) and approximately 4.0 million people in the United States have severely high triglyceride levels (TG >500mg/dL), commonly known as very high triglyceride levels. According to The American Heart Association Scientific Statement on Triglycerides and Cardiovascular Disease (2011), triglycerides also provide important information as a marker associated with the risk for heart disease and stroke, especially when an individual also has low high-density lipoprotein cholesterol, or HDL-C (often referred to as “good” cholesterol), and elevated levels of LDL-C (often referred to as “bad” cholesterol). Guidelines for the management of very high triglyceride levels suggest that reducing triglyceride levels is the primary goal in patients to reduce the risk of acute pancreatitis. The effect of Vascepa on cardiovascular mortality and morbidity, or the risk for pancreatitis, in patients with hypertriglyceridemia has not been determined. The potential efficacy and safety of Vascepa (known in its development stage as AMR 101) was studied in two Phase 3 clinical trials, the MARINE trial and the ANCHOR trial. At a daily dose of 4 grams of Vascepa, the dose at which Vascepa is FDA approved, these trials showed favorable clinical results in their respective patient populations in reducing triglyceride levels without increasing LDL-C levels in the MARINE trial and with a statistically significant decrease in LDL-C levels in the ANCHOR trial, in each case, relative to placebo. These trials also showed favorable results, particularly with the 4-gram dose of Vascepa, in other important lipid and inflammation biomarkers, including apolipoprotein B (apo B), non-high-density lipoprotein cholesterol (non-HDL-C), total-cholesterol (TC), very low-density lipoprotein cholesterol (VLDL-C), lipoprotein-associated phospholipase A2 (Lp-PLA2), and high sensitivity C-reactive protein (hs-CRP). In these trials, the most commonly reported adverse reaction (incidence >2% and greater than placebo) in Vascepa-treated patients was arthralgia (joint pain) (2.3% for Vascepa vs. 1.0% for placebo). The Company is also developing Vascepa for the treatment of patients with high (TG ³ 200 mg/dL and <500 mg/dL) triglyceride levels who are also on statin therapy for elevated low-density lipoprotein cholesterol, or LDL-C, levels which the Company refers to as mixed dyslipidemia. The Company refers to this second proposed indication for Vascepa as the ANCHOR indication. The FDA has stated that it views the proposed ANCHOR indication as ostensibly and impliedly an indication to reduce cardiovascular risk. In addition, in December 2011, Amarin announced commencement of patient dosing in a cardiovascular outcomes study of Vascepa, titled REDUCE-IT (Reduction of Cardiovascular Events with EPA—Intervention Trial). The REDUCE-IT study is designed to evaluate the efficacy of Vascepa in reducing major cardiovascular events in a high risk patient population on statin therapy. The Company has a pending supplemental new drug application, or sNDA, with the FDA that seeks marketing approval of Vascepa for use in the ANCHOR indication. On October 16, 2013, the FDA convened an advisory committee to review the sNDA. This advisory committee was not asked by the FDA to evaluate whether Vascepa is effective in lowering triglycerides in the studied population, the ANCHOR indication as specified in the sNDA. Rather, the advisory committee was asked whether Vascepa has been demonstrated to improve cardiovascular outcomes or whether approval of the ANCHOR indication should wait for successful completion of the REDUCE-IT study, the first prospective study of cardiovascular outcomes in patients who have high triglyceride levels despite statin therapy. The advisory committee voted 9 to 2 against recommending approval of the ANCHOR indication based on information presented at the meeting. The FDA considers the recommendation of advisory committee, but final decisions on the approval of new drug applications are made by the FDA. On October 22, 2013, in an effort to reduce operating expenses following the recommendation of the advisory committee, the Company implemented a worldwide reduction in force of approximately 50% of its staff positions (See Note 15 – Restructuring). The ANCHOR trial clinical study was conducted under a special protocol assessment, or SPA, agreement with the FDA. The law governing SPA agreements requires that if the results of the trial conducted under the SPA substantiate the hypothesis of the protocol covered by the SPA, the FDA must use the data from the protocol as part of the primary basis for approval of the product. A SPA agreement is not a guarantee of FDA approval of the related new drug application. A SPA agreement is generally binding upon the FDA, except in limited circumstances, such as if the FDA identifies a substantial scientific issue essential to determining safety or efficacy of the drug after the study begins that rises to the level of a public health concern, or if the study sponsor fails to follow the protocol that was agreed upon with the FDA. On October 29, 2013, the FDA rescinded the ANCHOR study SPA agreement because the FDA determined that a substantial scientific issue essential to determining the effectiveness of Vascepa in the studied population was identified after testing began. As a basis for this determination, the FDA communicated that it determined that the cumulative results from outcome studies of other triglyceride-lowering drugs failed to support the hypothesis that a triglyceride-lowering drug significantly reduces the risk for cardiovascular events among the population studied in the ANCHOR trial. Thus, the FDA stated that while information the Company submitted supports testing the hypothesis that Vascepa 4 grams/day versus placebo reduces major adverse cardiovascular events in statin-treated subjects with residually high triglyceride levels, as is being studied in the Vascepa REDUCE-IT cardiovascular outcomes study, the FDA no longer considers a change in serum triglyceride levels as sufficient to establish the effectiveness of a drug intended to reduce cardiovascular risk in subjects with serum triglyceride levels below 500 mg/dL. In November 2013, the Company submitted to the FDA a request for reconsideration of its decision to rescind the ANCHOR SPA agreement. On January 17, 2014, the Company was notified by the FDA that it does not intend to reinstate the ANCHOR SPA agreement. The Company plans to continue appealing the rescission decision to successively higher administrative levels within the FDA in accordance with FDA dispute resolution guidance. The FDA did not take action on the ANCHOR sNDA by the Prescription Drug User Fee Act, or PDUFA, goal date for completion of FDA’s review, December 20, 2013. Instead, the FDA notified the Company on December 19, 2013 that it would first consider our appeal of the ANCHOR SPA agreement rescission. No new PDUFA goal date for the ANCHOR sNDA was established. Based on information available, the Company does not expect a determination on the ANCHOR sNDA while the Company’s appeal of the January 17, 2014 FDA decision to uphold the ANCHOR SPA rescission is pending. The Company is also continuing its efforts toward a positive determination on the pending ANCHOR sNDA. There also can be no assurance that the FDA will not communicate the results of its review of the ANCHOR sNDA prior to the timing expected. Based on the Company’s communications with the FDA, the Company currently expects that final positive results from the REDUCE-IT outcomes study will be required for FDA approval of Vascepa for the ANCHOR indication. There can be no assurance that the Company will be successful in its efforts to reinstate the ANCHOR SPA agreement or obtain a label expansion reflecting the ANCHOR clinical trial. Such label expansion could include FDA approval of the addition of an ANCHOR indication statement and/or the addition of the ANCHOR clinical trial data to the currently approved labeling. If the FDA does not approve the ANCHOR indication, it could have a material impact on the Company’s future results of operations and financial condition. The Company has evaluated subsequent events from December 31, 2013 through the date of the issuance of these consolidated financial statements. See Note 17—Subsequent Events. *Basis of Presentation* The accompanying consolidated financial statements of the Company and subsidiaries are prepared in conformity with accounting principles generally accepted in the U.S. (GAAP) and have been prepared on a basis which assumes that the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. Prior to 2004, the Company was in the business of selling a previous biopharmaceutical compound, which has since been discontinued. The Company’s current focus is on the commercialization and development of Vascepa, which received approval from the FDA in 2012 and for which the Company commenced marketing and sales in 2013. At December 31, 2013, the Company had cash and cash equivalents of $191.5 million. The Company’s consolidated balance sheet also includes a derivative liability (see Note 7—Warrants and Warrant Derivative Liability) as well as Long term debt and Exchangeable Senior Notes (see Note 8—Debt). The derivative liability reflects the fair value of outstanding warrants to purchase shares of the Company’s common stock. The long term debt is not callable except upon a change in control. The Exchangeable Senior Notes may be redeemed on or after January 19, 2017 at the option of the holders. The Notes are exchangeable under certain circumstances into cash, American Depository Shares (ADSs), or a combination of cash and ADSs, at the Company’s election. Accordingly, the warrant derivative liability, long term debt and Exchangeable Senior Notes do not present a short term claim on the liquid assets of the Company. The Company believes its cash and cash equivalents will be sufficient to fund its operations for at least the next twelve months.

(1) Nature of Business and Basis of Presentation

Nature of Business

Amarin Corporation plc, “Amarin” or the “Company” is a biopharmaceutical company with expertise in lipid science focused on the commercialization and development of therapeutics to improve cardiovascular health.

Our lead product, Vascepa^® (icosapent ethyl) capsules, is approved by the U.S. Food and Drug Administration, or FDA, for use as an adjunct to diet to reduce triglyceride levels in adult patients with severe (TG >500mg/dL) hypertriglyceridemia. The Company refers to this approved indication for Vascepa as the MARINE indication. The Company began marketing and selling Vascepa in the United States in January 2013. Vascepa is available in the United States by prescription only. The Company markets Vascepa through its sales force of approximately 150 sales professionals, including sales representatives and their managers.

Triglycerides are fats in the blood. Hypertriglyceridemia refers to a condition in which patients have high levels of triglycerides in the bloodstream. It is estimated that over 40 million adults in the United States have elevated triglyceride levels (TG >200mg/dL) and approximately 4.0 million people in the United States have severely high triglyceride levels (TG >500mg/dL), commonly known as very high triglyceride levels. According to The American Heart Association Scientific Statement on Triglycerides and Cardiovascular Disease (2011), triglycerides also provide important information as a marker associated with the risk for heart disease and stroke, especially when an individual also has low high-density lipoprotein cholesterol, or HDL-C (often referred to as “good” cholesterol), and elevated levels of LDL-C (often referred to as “bad” cholesterol). Guidelines for the management of very high triglyceride levels suggest that reducing triglyceride levels is the primary goal in patients to reduce the risk of acute pancreatitis. The effect of Vascepa on cardiovascular mortality and morbidity, or the risk for pancreatitis, in patients with hypertriglyceridemia has not been determined.

The potential efficacy and safety of Vascepa (known in its development stage as AMR 101) was studied in two Phase 3 clinical trials, the MARINE trial and the ANCHOR trial. At a daily dose of 4 grams of Vascepa, the dose at which Vascepa is FDA approved, these trials showed favorable clinical results in their respective patient populations in reducing triglyceride levels without increasing LDL-C levels in the MARINE trial and with a statistically significant decrease in LDL-C levels in the ANCHOR trial, in each case, relative to placebo. These trials also showed favorable results, particularly with the 4-gram dose of Vascepa, in other important lipid and inflammation biomarkers, including apolipoprotein B (apo B), non-high-density lipoprotein cholesterol (non-HDL-C), total-cholesterol (TC), very low-density lipoprotein cholesterol (VLDL-C), lipoprotein-associated phospholipase A2 (Lp-PLA2), and high sensitivity C-reactive protein (hs-CRP). In these trials, the most commonly reported adverse reaction (incidence >2% and greater than placebo) in Vascepa-treated patients was arthralgia (joint pain) (2.3% for Vascepa vs. 1.0% for placebo).

The Company is also developing Vascepa for the treatment of patients with high (TG ³ 200 mg/dL and <500 mg/dL) triglyceride levels who are also on statin therapy for elevated low-density lipoprotein cholesterol, or LDL-C, levels which the Company refers to as mixed dyslipidemia. The Company refers to this second proposed indication for Vascepa as the ANCHOR indication. The FDA has stated that it views the proposed ANCHOR indication as ostensibly and impliedly an indication to reduce cardiovascular risk. In addition, in December 2011, Amarin announced commencement of patient dosing in a cardiovascular outcomes study of Vascepa, titled REDUCE-IT (Reduction of Cardiovascular Events with EPA—Intervention Trial). The REDUCE-IT study is designed to evaluate the efficacy of Vascepa in reducing major cardiovascular events in a high risk patient population on statin therapy.

The Company has a pending supplemental new drug application, or sNDA, with the FDA that seeks marketing approval of Vascepa for use in the ANCHOR indication. On October 16, 2013, the FDA convened an advisory committee to review the sNDA. This advisory committee was not asked by the FDA to evaluate whether Vascepa is effective in lowering triglycerides in the studied population, the ANCHOR indication as specified in the sNDA. Rather, the advisory committee was asked whether Vascepa has been demonstrated to improve cardiovascular outcomes or whether approval of the ANCHOR indication should wait for successful completion of the REDUCE-IT study, the first prospective study of cardiovascular outcomes in patients who have high triglyceride levels despite statin therapy. The advisory committee voted 9 to 2 against recommending approval of the ANCHOR indication based on information presented at the meeting. The FDA considers the recommendation of advisory committee, but final decisions on the approval of new drug applications are made by the FDA. On October 22, 2013, in an effort to reduce operating expenses following the recommendation of the advisory committee, the Company implemented a worldwide reduction in force of approximately 50% of its staff positions (See Note 15 – Restructuring).

The ANCHOR trial clinical study was conducted under a special protocol assessment, or SPA, agreement with the FDA. The law governing SPA agreements requires that if the results of the trial conducted under the SPA substantiate the hypothesis of the protocol covered by the SPA, the FDA must use the data from the protocol as part of the primary basis for approval of the product. A SPA agreement is not a guarantee of FDA approval of the related new drug application. A SPA agreement is generally binding upon the FDA, except in limited circumstances, such as if the FDA identifies a substantial scientific issue essential to determining safety or efficacy of the drug after the study begins that rises to the level of a public health concern, or if the study sponsor fails to follow the protocol that was agreed upon with the FDA. On October 29, 2013, the FDA rescinded the ANCHOR study SPA agreement because the FDA determined that a substantial scientific issue essential to determining the effectiveness of Vascepa in the studied population was identified after testing began. As a basis for this determination, the FDA communicated that it determined that the cumulative results from outcome studies of other triglyceride-lowering drugs failed to support the hypothesis that a triglyceride-lowering drug significantly reduces the risk for cardiovascular events among the population studied in the ANCHOR trial. Thus, the FDA stated that while information the Company submitted supports testing the hypothesis that Vascepa 4 grams/day versus placebo reduces major adverse cardiovascular events in statin-treated subjects with residually high triglyceride levels, as is being studied in the Vascepa REDUCE-IT cardiovascular outcomes study, the FDA no longer considers a change in serum triglyceride levels as sufficient to establish the effectiveness of a drug intended to reduce cardiovascular risk in subjects with serum triglyceride levels below 500 mg/dL. In November 2013, the Company submitted to the FDA a request for reconsideration of its decision to rescind the ANCHOR SPA agreement. On January 17, 2014, the Company was notified by the FDA that it does not intend to reinstate the ANCHOR SPA agreement. The Company plans to continue appealing the rescission decision to successively higher administrative levels within the FDA in accordance with FDA dispute resolution guidance.

The FDA did not take action on the ANCHOR sNDA by the Prescription Drug User Fee Act, or PDUFA, goal date for completion of FDA’s review, December 20, 2013. Instead, the FDA notified the Company on December 19, 2013 that it would first consider our appeal of the ANCHOR SPA agreement rescission. No new PDUFA goal date for the ANCHOR sNDA was established. Based on information available, the Company does not expect a determination on the ANCHOR sNDA while the Company’s appeal of the January 17, 2014 FDA decision to uphold the ANCHOR SPA rescission is pending. The Company is also continuing its efforts toward a positive determination on the pending ANCHOR sNDA. There also can be no assurance that the FDA will not communicate the results of its review of the ANCHOR sNDA prior to the timing expected.

Based on the Company’s communications with the FDA, the Company currently expects that final positive results from the REDUCE-IT outcomes study will be required for FDA approval of Vascepa for the ANCHOR indication. There can be no assurance that the Company will be successful in its efforts to reinstate the ANCHOR SPA agreement or obtain a label expansion reflecting the ANCHOR clinical trial. Such label expansion could include FDA approval of the addition of an ANCHOR indication statement and/or the addition of the ANCHOR clinical trial data to the currently approved labeling. If the FDA does not approve the ANCHOR indication, it could have a material impact on the Company’s future results of operations and financial condition.

The Company has evaluated subsequent events from December 31, 2013 through the date of the issuance of these consolidated financial statements. See Note 17—Subsequent Events.

Basis of Presentation

The accompanying consolidated financial statements of the Company and subsidiaries are prepared in conformity with accounting principles generally accepted in the U.S. (GAAP) and have been prepared on a basis which assumes that the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. Prior to 2004, the Company was in the business of selling a previous biopharmaceutical compound, which has since been discontinued. The Company’s current focus is on the commercialization and development of Vascepa, which received approval from the FDA in 2012 and for which the Company commenced marketing and sales in 2013.

At December 31, 2013, the Company had cash and cash equivalents of $191.5 million. The Company’s consolidated balance sheet also includes a derivative liability (see Note 7—Warrants and Warrant Derivative Liability) as well as Long term debt and Exchangeable Senior Notes (see Note 8—Debt). The derivative liability reflects the fair value of outstanding warrants to purchase shares of the Company’s common stock. The long term debt is not callable except upon a change in control. The Exchangeable Senior Notes may be redeemed on or after January 19, 2017 at the option of the holders. The Notes are exchangeable under certain circumstances into cash, American Depository Shares (ADSs), or a combination of cash and ADSs, at the Company’s election. Accordingly, the warrant derivative liability, long term debt and Exchangeable Senior Notes do not present a short term claim on the liquid assets of the Company.

The Company believes its cash and cash equivalents will be sufficient to fund its operations for at least the next twelve months.