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Cumulative payments received since inception of the collaboration agreement included in the transaction price for the performance obligation.

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No definition available.

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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 achieved during the period.

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No definition available.

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The number of medicines currently being developed under the collaboration agreement(s).

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Payments received under the collaboration agreement during the period included in the transaction price for the performance obligation.

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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, Biogen (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) Medicine	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue	$ 133,367	$ 297,214
SPINRAZA Royalties [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue	66,008	59,711
R&D Revenue [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue	$ 49,406	229,126
Biogen [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Number of medicines currently being developed \| Medicine	8
Cumulative payments received	$ 2,500,000
Revenue	87,400	$ 84,200
Deferred revenue	$ 512,300		$ 525,800
Biogen [Member] \| Revenue [Member] \| Strategic Partner [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Concentration percentage	66.00%	28.00%
Biogen [Member] \| SPINRAZA Royalties [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue	$ 66,000	$ 59,700
Biogen [Member] \| R&D Revenue [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue	21,400	$ 24,500
2012 Neurology [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Milestone payment achieved	7,500
Payments included in transaction price for performance obligation	7,500
2012 Neurology [Member] \| IONIS-MAPT [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Cumulative payments included in transaction price for performance obligation	$ 45,000