CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenue:
Revenue	$ 705,138	$ 787,647	$ 587,367
Expenses:
Cost of sales	11,215	9,133	14,116
Research, development and patent	901,530	899,625	833,147
Selling, general and administrative	267,474	232,619	150,295
Total operating expenses	1,180,219	1,141,377	997,558
Loss from operations	(475,081)	(353,730)	(410,191)
Other income (expense):
Investment income	107,022	89,041	25,331
Interest expense	(16,994)	(12,660)	(8,122)
Interest expense related to sale of future royalties	(73,457)	(68,797)	0
Loss on investments	(2,889)	(1,914)	(7,333)
Gain (loss) on sale of real estate assets	(12)	(161)	149,604
Other income (expense)	1,343	14,256	(7,274)
Loss before income tax benefit (expense)	(460,068)	(333,965)	(257,985)
Income tax benefit (expense)	6,171	(32,321)	(11,737)
Net loss	$ (453,897)	$ (366,286)	$ (269,722)
Basic net loss per share (in dollars per share)	$ (3.04)	$ (2.56)	$ (1.9)
Shares used in computing basic net loss per share (in shares)	149,514	143,190	141,848
Diluted net loss per share (in dollars per share)	$ (3.04)	$ (2.56)	$ (1.9)
Shares used in computing diluted net loss per share (in shares)	149,514	143,190	141,848
Commercial Revenue [Member]
Revenue:
Revenue	$ 293,076	$ 308,591	$ 303,358
SPINRAZA Royalties [Member]
Revenue:
Revenue	216,090	240,379	242,314
WAINUA Royalties [Member]
Revenue:
Revenue	20,207	0	0
Other Commercial Revenue [Member]
Revenue:
Revenue	56,779	68,212	61,044
Research and Development Revenue [Member]
Revenue:
Revenue	412,062	479,056	284,009
Collaborative Agreement Revenue [Member]
Revenue:
Revenue	332,647	352,657	207,222
WAINUA Joint Development Revenue [Member]
Revenue:
Revenue	$ 79,415	$ 126,399	$ 76,787