Liability Related to Sale of Future Royalties (Details) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
	Jan. 31, 2023	Jun. 30, 2023	Jun. 30, 2022
Royalty Revenue Monetization [Abstract]
Transaction costs		$ 10,434	$ 0
Proceeds from sale of future royalties		500,000	0
Royalty payments to Royalty Pharma		(12,562)	0
Interest expense related to sale of future royalties		32,915	0
Issuance costs related to sale of future royalties		(10,434)	$ 0
Net liability related to sale of future royalties		510,174
Royalty Purchase Agreement [Member]
Royalty Revenue Monetization [Abstract]
Upfront payment received	$ 500,000
Maximum amount of payments receivable for additional milestones		625,000
Transaction costs		$ 10,434
Effective interest rate		13.50%
Proceeds from sale of future royalties		$ 500,000
Royalty payments to Royalty Pharma		(12,562)
Interest expense related to sale of future royalties		32,915
Liability related to sale of future royalties as of		520,353
Issuance costs related to sale of future royalties		(10,434)
Amortization of issuance costs related to sale of future royalties		255
Net liability related to sale of future royalties		510,174
Royalty Purchase Agreement [Member] | SPINRAZA [Member]
Royalty Revenue Monetization [Abstract]
Maximum amount of annual sales on which royalty payments are paid		$ 1,500,000
Royalty Purchase Agreement [Member] | SPINRAZA [Member] | Minimum [Member]
Royalty Revenue Monetization [Abstract]
Percentage of royalty payments paid on annual sales of medicine		25.00%
Maximum royalty payments made before royalty interest reverts back		$ 475,000
Royalty Purchase Agreement [Member] | SPINRAZA [Member] | Maximum [Member]
Royalty Revenue Monetization [Abstract]
Percentage of royalty payments paid on annual sales of medicine		45.00%
Maximum royalty payments made before royalty interest reverts back		$ 550,000
Royalty Purchase Agreement [Member] | Pelacarsen [Member]
Royalty Revenue Monetization [Abstract]
Percentage of royalty payments paid on annual sales of medicine		25.00%