Development, Commercialization and Supply Agreement - Additional Information (Detail) - USD ($)		1 Months Ended													3 Months Ended				9 Months Ended		12 Months Ended
		Jun. 30, 2024	Jan. 31, 2024	Oct. 31, 2023	Jul. 31, 2023	Feb. 28, 2023	Jan. 31, 2023	Jan. 31, 2020	Dec. 31, 2019	Sep. 30, 2018	Sep. 30, 2017	Mar. 31, 2017	Mar. 31, 2016	Feb. 28, 2015	Sep. 30, 2024	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2018	Dec. 31, 2022
License And Collaboration Agreements [Line Items]
Revenue recognized related to upfront and milestone payments																$ 4,900,000		$ 15,000,000
Revenue recognized related to upfront and milestone payments																			$ 4,850,000	$ 15,372,000
Licenses revenue															$ 42,298,000		$ 66,056,000		166,308,000	232,198,000
Deferred revenue																	4,974,000			4,974,000	$ 4,850,000		$ 15,346,000
Product Revenue, Net
License And Collaboration Agreements [Line Items]
Licenses revenue															41,852,000		64,903,000		144,522,000	214,744,000
Marine
License And Collaboration Agreements [Line Items]
Revenue recognized related to upfront and milestone payments																		3,900,000
Mochida Pharmaceutical Co., Ltd. | In-licenses
License And Collaboration Agreements [Line Items]
Milestones payment			$ 1,000,000				$ 1,000,000
Mochida Pharmaceutical Co., Ltd. | In-licenses | Research and Development Expense
License And Collaboration Agreements [Line Items]
Up-front payment																						$ 2,700,000
Edding
License And Collaboration Agreements [Line Items]
Revenue recognized related to upfront and milestone payments																4,000,000		5,000,000
Edding | Achievement of REDUCE-IT Trial | VASCEPA
License And Collaboration Agreements [Line Items]
Non-refundable milestone payment received		$ 15,000,000
Edding | Out-licenses
License And Collaboration Agreements [Line Items]
Non-refundable up-front received														$ 15,000,000
Sales-based milestone event payment															120,000,000				120,000,000
Revenue recognized related to upfront and milestone payments	[1]																			9,400,000
Revenue recognized related to upfront and milestone payments	[1]																		19,426,000
Deferred revenue																					4,400,000
Edding | Out-licenses | Licensing Revenue
License And Collaboration Agreements [Line Items]
Licenses revenue																			40,081,000		$ 20,655,000
Edding | Out-licenses | Product Revenue, Net
License And Collaboration Agreements [Line Items]
Licenses revenue															4,800,000		300,000		8,200,000	300,000
Edding | Out-licenses | Maximum
License And Collaboration Agreements [Line Items]
Sales-based milestone event payment															50,000,000				50,000,000
Edding | Out-licenses | Minimum
License And Collaboration Agreements [Line Items]
Sales-based milestone event payment															5,000,000				5,000,000
Edding | Out-licenses | Clinical Trial Application
License And Collaboration Agreements [Line Items]
Non-refundable milestone payment received													$ 1,000,000
Edding | Out-licenses | Achievement of REDUCE-IT Trial
License And Collaboration Agreements [Line Items]
Non-refundable milestone payment received				$ 3,000,000
Edding | Out-licenses | Marine
License And Collaboration Agreements [Line Items]
Additional upfront payment eligible to receive based on development, regulatory and sales Milestone																		3,900,000
Additional license revenues															4,000,000		5,000,000		4,000,000	5,000,000
Revenue recognized related to upfront and milestone payments																$ 15,000,000
Remaining performance period amount															1,100,000				1,100,000
Reduction in net loss																			$ 4,000,000	5,000,000
Edding | Out-licenses | Marine | VASCEPA
License And Collaboration Agreements [Line Items]
Non-refundable milestone payment received												$ 5,000,000
Edding | Out-licenses | Marine | Maximum
License And Collaboration Agreements [Line Items]
Revenue recognition period of non-refundable up-front payment																			3 years
Edding | Out-licenses | Marine | Minimum
License And Collaboration Agreements [Line Items]
Revenue recognition period of non-refundable up-front payment																			11 years
Biologix FZCo
License And Collaboration Agreements [Line Items]
Revenue recognition period of non-refundable up-front payment																			8 years
Biologix FZCo | Out-licenses
License And Collaboration Agreements [Line Items]
Non-refundable milestone payment received																				5,300,000
Reduction in net loss																				5,300,000
Biologix FZCo | Out-licenses | Product Revenue, Net
License And Collaboration Agreements [Line Items]
Licenses revenue															1,300,000		1,400,000		$ 1,300,000	2,000,000
HLS
License And Collaboration Agreements [Line Items]
Revenue recognized related to upfront and milestone payments																		$ 5,300,000
HLS | Out-licenses
License And Collaboration Agreements [Line Items]
Non-refundable up-front received											$ 5,000,000
Non-refundable milestone payment received								$ 3,800,000
Revenue recognized related to upfront and milestone payments																				5,600,000
HLS | Out-licenses | Health Canada
License And Collaboration Agreements [Line Items]
Non-refundable milestone payment received									$ 2,500,000
HLS | Out-licenses | Product Revenue, Net
License And Collaboration Agreements [Line Items]
Licenses revenue															0		0		1,900,000	1,600,000
HLS | Out-licenses | Maximum
License And Collaboration Agreements [Line Items]
Additional upfront payment eligible to receive based on development, regulatory and sales Milestone											$ 50,000,000
HLS | Out-licenses | Achievement of REDUCE-IT Trial
License And Collaboration Agreements [Line Items]
Non-refundable milestone payment received										$ 2,500,000
CSL Seqirus | Out-licenses
License And Collaboration Agreements [Line Items]
Non-refundable up-front received						$ 500,000
Licenses revenue																	0			500,000
Upfront payment receivable						500,000
Event-related milestone payments receivable						8,000,000
Additional product-related milestone payments receivable						$ 4,000,000
CSL Seqirus | Out-licenses | Product Revenue, Net
License And Collaboration Agreements [Line Items]
Licenses revenue															$ 800,000				$ 800,000
Lotus Pharmaceuticals | VAZKEPA
License And Collaboration Agreements [Line Items]
Non-refundable up-front received					$ 300,000
Upfront payment receivable					$ 300,000
Lotus Pharmaceuticals | Out-licenses | Licensing Revenue
License And Collaboration Agreements [Line Items]
Licenses revenue																	$ 300,000			$ 300,000

[1] Licensing revenue under the DCS Agreement is recognized concurrent with the input measure of support hours provided by Amarin to Edding in achieving the combined development and regulatory performance obligation, which in the Company’s judgment is the best measure of progress towards satisfying this performance obligation.