CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue:
Revenue	$ 810,456	$ 729,264	$ 1,122,599
Expenses:
Cost of sales	10,842	11,947	4,384
Research, development and patent	643,453	535,077	465,688
Selling, general and administrative	186,347	354,322	286,644
Total operating expenses	840,642	901,346	756,716
Income (loss) from operations	(30,186)	(172,082)	365,883
Other income (expense):
Investment income	10,044	30,562	52,013
Interest expense	(9,349)	(9,510)	(12,440)
Gain on investments	10,103	16,540	192
Loss on early retirement of debt	(8,627)	0	(66,196)
Other expenses	(1,133)	(62)	(686)
Income (loss) before income tax benefit (expense)	(29,148)	(134,552)	338,766
Income tax benefit (expense)	551	(345,191)	(51,507)
Net income (loss)	(28,597)	(479,743)	287,259
Net (income) loss attributable to noncontrolling interest in Akcea Therapeutics, Inc.	0	35,480	(9,116)
Net income (loss) attributable to Ionis Pharmaceuticals, Inc. common stockholders	$ (28,597)	$ (444,263)	$ 278,143
Basic net income (loss) per share (in dollars per share)	$ (0.20)	$ (3.18)	$ 2.00
Shares used in computing basic net income (loss) per share (in shares)	141,021	139,612	139,998
Diluted net income (loss) per share (in dollars per share)	$ (0.20)	$ (3.18)	$ 1.90
Shares used in computing diluted net income (loss) per share (in shares)	141,021	139,612	153,164
Commercial Revenue [Member]
Revenue:
Revenue	$ 342,395	$ 364,699	$ 352,450
SPINRAZA Royalties [Member]
Revenue:
Revenue	267,776	286,583	292,992
TEGSEDI and WAYLIVRA Revenue, Net [Member]
Revenue:
Revenue	55,500	69,999	42,253
Licensing and Other Royalty Revenue [Member]
Revenue:
Revenue	19,119	8,117	17,205
Research and Development Revenue Under Collaborative Agreements [Member]
Revenue:
Revenue	$ 468,061	$ 364,565	$ 770,149