No definition available.

Name:	ions_CollaborativeArrangementAndLicensingAgreementAbstract
Namespace Prefix:	ions_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Cumulative amount of milestone payments, license fees and/or upfront fees received under the collaborative arrangement as of the end of the reporting period.

+ References

No definition available.

+ Details

Name:	ions_CumulativePaymentsAndOrFeesReceived
Namespace Prefix:	ions_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the maximum amount of milestone payments payable under the agreement.

+ References

No definition available.

+ Details

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

- Definition

Represents the maximum amount of payments receivable per drug or program under the agreement.

+ References

No definition available.

+ Details

Name:	ions_MaximumAmountOfPaymentsReceivablePerDrugOrProgram
Namespace Prefix:	ions_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the next potential milestone payment to be earned.

+ References

No definition available.

+ Details

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

- Definition

The number of therapeutic programs under the collaboration agreement.

+ References

No definition available.

+ Details

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

- Definition

The number of therapeutic targets granted by the partner under the collaboration agreement.

+ References

No definition available.

+ Details

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

- Definition

The number of therapeutic targets granted to the partner under the collaboration agreement.

+ References

No definition available.

+ Details

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

- Definition

Amount of deferred revenue recognized for transactions arising during the current reporting period. Deferred revenue is a liability as of the balance sheet date related to a revenue producing activity for which revenue has not yet been recognized. Generally, an Entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 13.A.4(a).Q1)
-URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 13
-Section A

+ Details

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

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

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

- Details

Name:	us-gaap_CounterpartyNameAxis=ions_AlnylamPharmaceuticalsIncMember
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Data Type:	na
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- Details

Name:	us-gaap_TypeOfArrangementAxis=ions_SatelliteCompanyCollaborativeArrangementAndLicensingAgreementMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	ions_AchievementOfMilestoneAxis=ions_PreSpecifiedEventsMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	ions_AchievementOfMilestoneAxis=ions_DevelopmentMilestonesMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	ions_AchievementOfMilestoneAxis=ions_RegulatoryMilestonesMember
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Collaborative Arrangements and Licensing Agreements, Satellite Company Collaborations - Alnylam Pharmaceuticals, Inc. (Details) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Mar. 31, 2004 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) Target Program	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue earned		$ 51,571	$ 49,121	$ 120,428	$ 62,583	$ 84,861	$ 44,063	$ 57,076	$ 28,161	$ 283,703	$ 214,161	$ 147,285
Alnylam Pharmaceuticals, Inc. [Member] \| Satellite Company Collaboration and Licensing Agreement [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Upfront fee recorded as deferred revenue	$ 5,000
Next potential milestone		400								$ 400
Number of therapeutic targets granted to Ionis \| Target										4
Number of therapeutic targets granted by Ionis \| Target										4
Number of therapeutic programs \| Program										4
Cumulative payments and/or fees received		70,000								$ 70,000
Revenue earned										1,300	$ 9,900	$ 1,500
Alnylam Pharmaceuticals, Inc. [Member] \| Satellite Company Collaboration and Licensing Agreement [Member] \| Pre Specified Events [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payments receivable per drug		3,400								3,400
Maximum amount of milestone payments payable		$ 3,400								$ 3,400
Alnylam Pharmaceuticals, Inc. [Member] \| Satellite Company Collaboration and Licensing Agreement [Member] \| Development Milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payments receivable per drug			1,100
Alnylam Pharmaceuticals, Inc. [Member] \| Satellite Company Collaboration and Licensing Agreement [Member] \| Regulatory Milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payments receivable per drug			$ 2,300