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Cumulative amount of payments received under the collaboration agreement as of the end of the reporting period.

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The next payment to be achieved under the collaboration agreement.

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The number of collaboration agreements with the collaboration partner.

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Number of early-stage programs to be developed for RNA-targeting investigational medicines for the treatment of Alzheimer's disease (AD) and Huntington's disease (HD).

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No definition available.

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The number of performance obligations identified under the collaboration agreement.

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

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No definition available.

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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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, 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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Collaborative Arrangements and Licensing Agreements, Roche (Details) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Oct. 31, 2023 USD ($)	Sep. 30, 2023 USD ($) Agreement PerformanceObligation Program	Sep. 30, 2023 USD ($) Agreement Program	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) Agreement Program	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue			$ 144,207	$ 159,767	$ 463,142	$ 435,478
R&D Revenue [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue			$ 60,126	$ 87,357	$ 233,396	$ 212,599
Roche [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Number of collaboration agreements \| Agreement		3	3		3
Deferred contract revenue		$ 68,000	$ 68,000		$ 68,000		$ 22,400
Roche [Member] \| Revenue [Member] \| Strategic Partner [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Concentration percentage			6.00%	26.00%	4.00%	15.00%
Roche [Member] \| Minimum [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Cumulative payments received		$ 285,000	$ 285,000		$ 285,000
Roche [Member] \| R&D Revenue [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue			$ 8,858	$ 41,504	$ 16,979	$ 65,360
HD [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Number of collaboration agreements \| Agreement		1	1		1
IONIS-FB-L for Complement-Mediated Diseases [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Number of collaboration agreements \| Agreement		1	1		1
RNA-targeted Programs for AD and HD [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Number of collaboration agreements \| Agreement		1	1		1
Number of early-stage programs \| Program		2	2		2
Number of identified performance obligations \| PerformanceObligation		2
Next payment to be achieved		$ 7,500	$ 7,500		$ 7,500
RNA-targeted Programs for AD and HD [Member] \| Subsequent Event [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Upfront payment received	$ 60,000