Subsequent Events	12 Months Ended
Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	(17) Subsequent Events On February 22, 2019, a class action lawsuit was filed against Amarin Corporation plc, the Company’s chief executive officer and chief scientific officer in the U.S. District Court for the District of New Jersey. See Note 8—Commitments and Contingencies for further information. On February 5, 2019, the Company entered into a lease agreement for approximately 67,747 square feet of new office space in Bridgewater, New Jersey (the “Lease”). The Lease will commence upon delivery of the premises after certain improvements are made, which is anticipated to be on or about July 1, 2019 (the “Commencement Date”) for an 11-year period, with two five-year renewal options. Subject to the terms of the Lease, Amarin will have a one-time option to terminate the agreement effective on the first day of the ninety-seventh month after the Commencement Date upon advanced written notice and a termination payment specified in the Lease. Under the Lease, the Company will pay monthly rent of approximately $141,000 for the first year following the Commencement Date, and such rent will increase by a nominal percentage every year following the first anniversary of the Commencement Date.

Subsequent Events

12 Months Ended

Dec. 31, 2018

(17) Subsequent Events

On February 22, 2019, a class action lawsuit was filed against Amarin Corporation plc, the Company’s chief executive officer and chief scientific officer in the U.S. District Court for the District of New Jersey. See Note 8—Commitments and Contingencies for further information.

On February 5, 2019, the Company entered into a lease agreement for approximately 67,747 square feet of new office space in Bridgewater, New Jersey (the “Lease”). The Lease will commence upon delivery of the premises after certain improvements are made, which is anticipated to be on or about July 1, 2019 (the “Commencement Date”) for an 11-year period, with two five-year renewal options. Subject to the terms of the Lease, Amarin will have a one-time option to terminate the agreement effective on the first day of the ninety-seventh month after the Commencement Date upon advanced written notice and a termination payment specified in the Lease. Under the Lease, the Company will pay monthly rent of approximately $141,000 for the first year following the Commencement Date, and such rent will increase by a nominal percentage every year following the first anniversary of the Commencement Date.