Additional amount of payments receivable per drug or program for regulatory milestone.

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- Definition

Consideration amount received.

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- Definition

The maximum amount of payments receivable for commercialization milestones under the collaboration agreement.

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- Definition

The maximum amount of payments receivable for development milestones under the collaboration agreement.

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The maximum amount of payments receivable for milestones under the collaboration agreement.

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The maximum amount of payments receivable for regulatory milestones under the collaboration agreement.

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Milestone payments and royalties payable percentage.

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Milestone payments and royalties retained percentage.

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- Definition

The next potential milestone payment to be earned under the collaboration agreement.

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- Definition

Period of time before collaboration partner pays royalties on net sales of product after first commercial sale in Brazil, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

The number of separate performance obligations under the collaboration agreement.

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The amount of consideration the Company is eligible to earn under the collaboration agreement, including any variable consideration.

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The minimum amount of revenue recognized in Latin America by the collaboration partner before paying royalties.

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Royalty percentage received on the sales of a drug by a collaboration partner under the collaboration agreement.

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Sublicense fee paid by issuance of common stock.

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The amount of the sublicense fee paid in cash.

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Upfront license fee receivable under license agreement.

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The amount of upfront payments received during the period under the collaboration agreement.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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Number of new stock issued during the period.

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Revenue from Collaboration and License Agreements - Narratives (Details)		1 Months Ended		3 Months Ended			6 Months Ended
	Aug. 01, 2018 USD ($)	May 31, 2019 USD ($)	Feb. 28, 2019 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($) shares	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) shares	Jun. 30, 2019 USD ($)	Oct. 31, 2019 USD ($) PerformanceObligation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue				$ 22,377,000		$ 26,623,000	$ 38,451,000	$ 190,439,000
Cardiometabolic License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sublicense fee paid		$ 3,000,000.0
TTR License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sublicense fee paid		2,400,000
Ionis [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sublicense fee paid				75,000,000.0			$ 75,000,000.0
Ionis [Member] \| Common Stock [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of stock (in shares) \| shares							2,837,373
Licensing [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue			$ 150,000,000.0			6,036,000		$ 6,036,000
AKCEA-APO(a)-L [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Maximum amount of payments receivable for milestones				675,000,000.0			$ 675,000,000.0
Maximum amount of payments receivable for development milestones				25,000,000.0			25,000,000.0
Maximum amount of payments receivable for regulatory milestones				290,000,000.0			290,000,000.0
Maximum amount of payments receivable for commercialization milestones				360,000,000.0			$ 360,000,000.0
Royalty percentage received on sales of drug							20.00%
License Agreement with Pfizer [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment received					$ 250,000,000.0
Issuance of stock (in shares) \| shares					6,873,344
Sublicense fee paid					$ 125,000,000.0
Number of separate performance obligations \| PerformanceObligation									3
Upfront license fee receivable					250,000,000.0
Transaction price					250,000,000.0
Revenue recognized upon delivery of the vupanorasen API							$ 5,300,000
Revenue recognized from deferred revenue				500,000			1,100,000
Deferred revenue				300,000	1,300,000		300,000
License Agreement with Pfizer [Member] \| Transfer of License of AKCEA-ANGPTL3-LRx [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price					245,600,000
License Agreement with Pfizer [Member] \| Development services for AKCEA-ANGPTL3-LRx [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price					2,200,000
License Agreement with Pfizer [Member] \| Delivery of AKCEA-ANGPTL3-LRx API [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price					2,200,000
License Agreement with Pfizer [Member] \| AKCEA-ANGPTL3-LRx [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Maximum amount of payments receivable for milestones					1,300,000,000
Maximum amount of payments receivable for development milestones					205,000,000.0
Maximum amount of payments receivable for regulatory milestones					250,000,000.0
Maximum amount of payments receivable for commercialization milestones					850,000,000.0
Next prospective milestone					$ 75,000,000.0
Royalty percentage received on sales of drug					20.00%
Novartis [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Next prospective milestone				25,000,000.0			25,000,000.0
Novartis [Member] \| AKCEA-APOCIII-LRx [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount expended on research and development expense							$ 2,300,000
Collaboration and License Agreement with PTC Therapeutics [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue					$ 4,000,000.0	$ 6,000,000.0
Milestone payment received		$ 6,000,000.0							$ 4,000,000.0
Collaboration and License Agreement with PTC Therapeutics [Member] \| Akcea [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognized upon delivery of the vupanorasen API	$ 10,000,000.0
Additional amount of payments receivable per drug for regulatory milestone	$ 4,000,000.0
Period before PTC pays royalties on net sales of product after first commercial sale in Brazil	12 months
Collaboration and License Agreement with PTC Therapeutics [Member] \| TEGSEDI [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue				$ 0
Collaboration and License Agreement with PTC Therapeutics [Member] \| TEGSEDI [Member] \| Akcea [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments and royalties retained percentage	40.00%
Collaboration and License Agreement with PTC Therapeutics [Member] \| TEGSEDI [Member] \| Ionis [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments and royalties payable percentage	60.00%