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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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No definition available.

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Milestone payment earned during the period and recognized as revenue as services are performed.

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No definition available.

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The next payment to be achieved 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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- Definition

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

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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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Collaborative Arrangements and Licensing Agreements, Biogen (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Apr. 30, 2023	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue		$ 130,524	$ 141,919
SPINRAZA Royalties [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue		50,247	53,818
R&D Revenue [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue		62,756	69,634
Biogen Collaborations [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue		70,501	$ 93,867
Deferred revenue		$ 340,900		$ 351,200
Biogen Collaborations [Member] \| Revenue [Member] \| Strategic Partner [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Concentration percentage		54.00%	66.00%
Biogen Collaborations [Member] \| Minimum [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Cumulative payments received		$ 3,500,000
Biogen Collaborations [Member] \| SPINRAZA Royalties [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue		50,247	$ 53,818
Biogen Collaborations [Member] \| R&D Revenue [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue		20,254	$ 40,049
2012 Neurology [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Milestone payment earned		10,000
2012 Neurology [Member] \| Maximum [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Next payment to be achieved		$ 25,000
2013 Strategic Neurology [Member] \| Maximum [Member] \| Subsequent Event [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Next payment to be achieved	$ 20,000
2013 Strategic Neurology [Member] \| Tofersen [Member] \| Subsequent Event [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue	$ 16,000