Collaborative Arrangements and Licensing Agreements, Roche (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2023 USD ($) PerformanceObligation	Dec. 31, 2024 USD ($) Program	Dec. 31, 2023 USD ($) PerformanceObligation	Dec. 31, 2022 USD ($)	Oct. 31, 2018 PerformanceObligation	Dec. 31, 2013 USD ($) PerformanceObligation
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue		$ 705,138	$ 787,647	$ 587,367
Roche [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue		39,871	48,838	$ 67,202
Deferred contract revenue	$ 36,700	$ 7,700	$ 36,700
Roche [Member] | Revenue [Member] | Strategic Partner [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Concentration percentage		6.00%	6.00%	11.00%
Sefaxersen [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payments receivable over term of collaboration		$ 430,000
Maximum amount of license fees over term of collaboration		35,000
Maximum amount of development milestone payments over term of collaboration		25,000
Maximum amount of regulatory milestone payments over term of collaboration		90,000
Maximum amount of sales milestone payments over term of collaboration		$ 280,000
Royalty percentage received on net sales of medicine		20.00%
Cumulative payments received		$ 140,000
Next payment to be achieved		23,500
Number of separate performance obligations | PerformanceObligation					1
Cumulative payments included in transaction price for performance obligation		97,000
Revenue				$ 35,000
HD [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payments receivable over term of collaboration		395,000
Maximum amount of upfront payments over term of collaboration		30,000
Maximum amount of license fees over term of collaboration		45,000
Maximum amount of development milestone payments over term of collaboration		70,000
Maximum amount of regulatory milestone payments over term of collaboration		170,000
Maximum amount of sales milestone payments over term of collaboration		80,000
Maximum amount of milestone payments for each additional medicine successfully developed over term of collaboration		136,500
Cumulative payments received		150,000
Next payment to be achieved		$ 17,500
Number of separate performance obligations | PerformanceObligation						1
Transaction price						$ 30,000
RNA-targeted Programs for AD and HD [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Number of early-stage programs | Program		2
Maximum amount of payments receivable over term of collaboration		$ 625,000
Upfront payment received	$ 60,000
Maximum amount of development milestone payments over term of collaboration		167,000
Maximum amount of sales milestone payments over term of collaboration		398,000
Cumulative payments received		60,000
Next payment to be achieved		$ 7,500
Number of separate performance obligations | PerformanceObligation	2		2
Transaction price	$ 60,000		$ 60,000
RNA-targeted Programs for AD and HD [Member] | R&D Services for Investigational Medicine for AD [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Transaction price	45,000		45,000
RNA-targeted Programs for AD and HD [Member] | R&D Services for Investigational Medicine for HD [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Transaction price	$ 15,000		$ 15,000