CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenue:
Revenue	$ 133,814	$ 144,207	$ 478,562	$ 463,142
Expenses:
Cost of sales	1,071	2,191	7,385	6,071
Research, development and patent	219,761	215,330	656,040	643,070
Selling, general and administrative	61,638	69,951	179,395	161,608
Total operating expenses	282,470	287,472	842,820	810,749
Loss from operations	(148,656)	(143,265)	(364,258)	(347,607)
Other income (expense):
Investment income	26,228	23,935	78,112	63,355
Interest expense	(4,161)	(4,203)	(12,803)	(8,102)
Interest expense related to sale of future royalties	(18,533)	(17,779)	(54,788)	(50,948)
Gain (loss) on investments	879	(1,943)	(321)	(1,753)
Other income	142	2,447	1,029	13,857
Loss before income tax benefit (expense)	(144,101)	(140,808)	(353,029)	(331,198)
Income tax benefit (expense)	3,621	(6,602)	3,481	(25,825)
Net loss	$ (140,480)	$ (147,410)	$ (349,548)	$ (357,023)
Basic net loss per share (in dollars per share)	$ (0.95)	$ (1.03)	$ (2.38)	$ (2.5)
Diluted net loss per share (in dollars per share)	$ (0.95)	$ (1.03)	$ (2.38)	$ (2.5)
Shares used in computing basic net loss per share (in shares)	148,593	143,317	146,703	143,052
Shares used in computing diluted net loss per share (in shares)	148,593	143,317	146,703	143,052
Commercial Revenue [Member]
Revenue:
Revenue	$ 75,731	$ 84,081	$ 207,360	$ 229,746
SPINRAZA Royalties [Member]
Revenue:
Revenue	57,208	67,253	152,406	178,511
WAINUA Royalties [Member]
Revenue:
Revenue	5,371	0	10,278	0
Other Commercial Revenue [Member]
Revenue:
Revenue	13,152	16,828	44,676	51,235
Research and Development Revenue [Member]
Revenue:
Revenue	58,083	60,126	271,202	233,396
Collaborative Agreement Revenue [Member]
Revenue:
Revenue	44,883	44,167	235,753	173,513
WAINUA Joint Development Revenue [Member]
Revenue:
Revenue	$ 13,200	$ 15,959	$ 35,449	$ 59,883