The number of agreements entered into with the collaboration partner.

No definition available.

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- Definition

The number of material components identified in the collaboration agreement under Accounting Standards Codification (ASC) 808, Collaborative Arrangements.

+ References

No definition available.

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- Definition

Number of targets advanced under the collaboration agreement.

+ References

No definition available.

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- Definition

Percentage of costs associated with the ongoing global Phase 3 development program paid by a collaboration partner under the collaboration agreement.

+ References

No definition available.

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- Definition

The number of separate performance obligations under the collaboration agreement.

+ References

No definition available.

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

The additional amount of consideration the Company earned under the collaboration agreement that is added to the transaction price.

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

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- References

No definition available.

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- Definition

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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Significant Accounting Policies, Revenue Recognition (Details) $ in Thousands	3 Months Ended						12 Months Ended
	Mar. 31, 2022 USD ($) Target	Dec. 31, 2021 USD ($) PerformanceObligation Component	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2018 Agreement	Dec. 31, 2021 USD ($) PerformanceObligation Component
Revenue Recognition [Abstract]
Revenue	$ 141,919		$ 111,607
Biogen [Member]
Revenue Recognition [Abstract]
Number of agreements \| Agreement						2
ION859 [Member]
Revenue Recognition [Abstract]
Revenue	10,000
Biogen 2013 Strategic Neurology [Member]
Revenue Recognition [Abstract]
Revenue	$ 18,000
Number of targets advanced \| Target	2
New Antisense Medicines for the Treatment of SMA [Member] \| ION306 [Member]
Revenue Recognition [Abstract]
Revenue		$ 60,000
Alnylam [Member]
Revenue Recognition [Abstract]
Revenue				$ 41,200
IONIS-FB-L for Complement-Mediated Diseases [Member]
Revenue Recognition [Abstract]
Upfront payment received					$ 75,000
Biogen 2018 Strategic Neurology [Member]
Revenue Recognition [Abstract]
Milestone payment received and added to transaction price		$ 7,500
Eplontersen Collaboration with AstraZeneca [Member]
Revenue Recognition [Abstract]
Revenue							$ 200,000
Number of material components \| Component		4					4
Number of separate performance obligations \| PerformanceObligation		1					1
Transaction price		$ 200,000					$ 200,000
Percentage of costs associated with ongoing global Phase 3 development program paid by AstraZeneca	55.00%