The number of agreements entered into with the collaboration partner.

No definition available.

Name:	ions_NumberOfAgreementsWithCollaborationPartner
Namespace Prefix:	ions_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of new targets advanced during the period under the collaboration agreement.

+ References

No definition available.

+ Details

Name:	ions_NumberOfNewTargetsAdvanced
Namespace Prefix:	ions_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of separate performance obligations under the collaboration agreement.

+ References

No definition available.

+ Details

Name:	ions_RevenueFromContractWithCustomerNumberOfSeparatePerformanceObligations
Namespace Prefix:	ions_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of consideration the Company earned or is eligible to earn under the collaboration agreement, including any variable consideration.

+ References

No definition available.

+ Details

Name:	ions_RevenueFromContractWithCustomerTransactionPrice
Namespace Prefix:	ions_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The additional amount of consideration the Company earned under the collaboration agreement that is added to the transaction price.

+ References

No definition available.

+ Details

Name:	ions_RevenueFromContractWithCustomerTransactionPriceAdditions
Namespace Prefix:	ions_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of upfront payments received during the period under the collaboration agreement.

+ References

No definition available.

+ Details

Name:	ions_UpfrontPaymentReceived
Namespace Prefix:	ions_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_RevenueFromContractWithCustomerAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8906-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9031-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9038-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130543-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130545-203045

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	srt_MajorCustomersAxis=ions_BiogenIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=us-gaap_ProductMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=ions_PtcTherapeuticsCollaborationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=ions_AstrazenecaCollaborationEplontersenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=ions_EplontersenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=ions_AstrazenecaCollaborationCardiovascularRenalAndMetabolicDiseasesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=ions_RocheCollaborationIonisFbLForComplementMediatedDiseasesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=ions_BiogenCollaboration2018StrategicNeurologyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=ions_BiogenCollaborationNewAntisenseMedicinesForTreatmentOfSmaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=ions_Ion306Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=ions_AlnylamCollaborationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=ions_BayerCollaborationIonisFxiMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=ions_BayerCollaborationIonisFxiAmendmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Organization and Significant Accounting Policies, Revenue Recognition (Details) $ in Thousands	1 Months Ended				3 Months Ended								12 Months Ended
	Dec. 31, 2021 USD ($) PerformanceObligation	Feb. 28, 2017 USD ($) PerformanceObligation	Jul. 31, 2015 USD ($) PerformanceObligation	May 31, 2015 USD ($) PerformanceObligation	Dec. 31, 2021 USD ($) Target PerformanceObligation	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($) Agreement	Dec. 31, 2017 USD ($) PerformanceObligation	Jun. 30, 2015 USD ($)	Dec. 31, 2021 USD ($) PerformanceObligation	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Oct. 31, 2018 USD ($) PerformanceObligation	Apr. 30, 2018 USD ($) PerformanceObligation
Revenue Recognition [Abstract]
Revenue													$ 810,456	$ 729,264	$ 1,122,599
Biogen [Member]
Revenue Recognition [Abstract]
Number of agreements \| Agreement										2
TEGSEDI and WAYLIVRA [Member]
Revenue Recognition [Abstract]
Revenue													$ 55,500	$ 69,999	$ 42,253
PTC Therapeutics [Member] \| TEGSEDI and WAYLIVRA [Member]
Revenue Recognition [Abstract]
Revenue						$ 4,000
AstraZeneca [Member]
Revenue Recognition [Abstract]
Revenue	$ 200,000
Upfront payment received	$ 200,000
Number of separate performance obligations \| PerformanceObligation	1				1								1
Transaction price	$ 200,000				$ 200,000								$ 200,000
AstraZeneca [Member] \| Eplontersen [Member]
Revenue Recognition [Abstract]
Revenue					200,000
AstraZeneca [Member]
Revenue Recognition [Abstract]
Revenue					10,000								$ 10,000
Upfront payment received			$ 65,000
Number of separate performance obligations \| PerformanceObligation			1
Transaction price			$ 65,000
Roche IONIS-FB-L for Complement-Mediated Diseases [Member]
Revenue Recognition [Abstract]
Revenue							$ (9,200)
Upfront payment received									$ 75,000
Number of separate performance obligations \| PerformanceObligation																1
Transaction price																$ 75,000
Biogen 2018 Strategic Neurology [Member]
Revenue Recognition [Abstract]
Revenue					15,000
Upfront payment received										$ 375,000
Milestone payment received and added to transaction price					$ 7,500
Number of new targets advanced \| Target					2
Number of separate performance obligations \| PerformanceObligation																	1
Transaction price																	$ 552,000
Biogen Treatment of SMA [Member]
Revenue Recognition [Abstract]
Revenue								$ 8,300
Upfront payment received											$ 25,000
Number of separate performance obligations \| PerformanceObligation											1
Transaction price											$ 25,000
Biogen Treatment of SMA [Member] \| ION306 [Member]
Revenue Recognition [Abstract]
Revenue	$ 60,000				$ 60,000
Alnylam [Member]
Revenue Recognition [Abstract]
Revenue							$ 41,200
Bayer [Member]
Revenue Recognition [Abstract]
Upfront payment received				$ 100,000								$ 100,000
Number of separate performance obligations \| PerformanceObligation				3
Bayer [Member]
Revenue Recognition [Abstract]
Upfront payment received		$ 75,000
Number of separate performance obligations \| PerformanceObligation		3
Transaction price		$ 75,000