Long-Term Obligations and Commitments, Royalty Revenue Monetization (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Royalty Revenue Monetization [Abstract]
Upfront payment received	$ 500,000
Maximum amount of payments receivable for additional milestones	625,000
Transaction costs		$ 10,434	$ 29	$ 0
Proceeds from sale of future royalties		500,000	0	0
Royalty payments to Royalty Pharma		(44,628)	0	0
Interest expense related to sale of future royalties		68,238	0	0
Issuance costs related to sale of future royalties		(10,434)	(29)	$ 0
Net liability related to sale of future royalties		513,736	$ 0
SPINRAZA [Member]
Royalty Revenue Monetization [Abstract]
Maximum amount of annual sales on which royalty payments are paid	$ 1,500,000	$ 1,500,000
SPINRAZA [Member] | Minimum [Member]
Royalty Revenue Monetization [Abstract]
Percentage of royalty payments paid on annual sales of medicine	25.00%	25.00%
Maximum royalty payments made before royalty interest reverts back	$ 475,000	$ 475,000
SPINRAZA [Member] | Maximum [Member]
Royalty Revenue Monetization [Abstract]
Percentage of royalty payments paid on annual sales of medicine	45.00%	45.00%
Maximum royalty payments made before royalty interest reverts back	$ 550,000	$ 550,000
Pelacarsen [Member]
Royalty Revenue Monetization [Abstract]
Percentage of royalty payments paid on annual sales of medicine	25.00%
Royalty Purchase Agreement [Member]
Royalty Revenue Monetization [Abstract]
Transaction costs		$ 10,434
Effective interest rate		13.50%
Proceeds from sale of future royalties		$ 500,000
Royalty payments to Royalty Pharma		(44,628)
Interest expense related to sale of future royalties		68,238
Liability related to sale of future royalties		523,610
Issuance costs related to sale of future royalties		(10,434)
Amortization of issuance costs related to sale of future royalties		560
Net liability related to sale of future royalties		$ 513,736