Name:	ions_AssumedChangeInEstimatedSellingPriceOfProduct
Namespace Prefix:	ions_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The amount of change to the allocation of the consideration to a specific unit of accounting that would result from a specified change in the selling price factor applied to a multiple-deliverable arrangement.

No definition available.

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

The number of categories of milestone events used in collaboration agreements to determine milestone payments.

No definition available.

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

The number of drugs licensed after the partner(s) exercised their option to license the Company's drugs under their respective collaboration agreements.

No definition available.

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

The number of drugs that can be licensed by the partner(s) under their respective collaboration agreements.

No definition available.

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

The number of partners that exercised their option to license drugs from the Company under a collaboration agreement.

No definition available.

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

The number of stages in the life-cycle of drugs.

No definition available.

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

The number of targets for the research and development of drugs under the collaboration agreement.

No definition available.

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

The percentage change to the allocation of the consideration to a specific unit of accounting that would result from a specified change in the selling price factor applied to a multiple-deliverable arrangement.

No definition available.

Name:	ions_PercentageChangeInAmountOfRevenueFromProductForAssumedChangeInSellingPrice
Namespace Prefix:	ions_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The average time period to complete Investigational New Drug (IND)-enabling animal studies for a new development candidate, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	ions_PeriodToCompleteINDEnablingAnimalStudies
Namespace Prefix:	ions_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The average time period to complete a Phase 1 clinical trial, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	ions_PeriodToCompletePhase1ClinicalTrial
Namespace Prefix:	ions_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The average time period to complete a Phase 2 clinical trial, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	ions_PeriodToCompletePhase2ClinicalTrial
Namespace Prefix:	ions_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The average time period to complete a Phase 3 clinical trial, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	ions_PeriodToCompletePhase3ClinicalTrial
Namespace Prefix:	ions_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The average time period to obtain marketing authorization from the applicable regulatory agency after an application is submitted, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	ions_PeriodToObtainMarketingAuthorizationFromApplicableRegulatoryAgency
Namespace Prefix:	ions_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The average time period to prepare and submit regulatory filngs, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	ions_PeriodToPrepareAndSubmitRegulatoryFilings
Namespace Prefix:	ions_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Amount of a pre-specified sales threshold that can be used to trigger a commercialization milestone payment under the collaboration agreement.

No definition available.

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

Represents the number of separate units of accounting requiring the allocation of consideration for revenue recognition purposes under the multi-deliverable arrangement.

No definition available.

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

Term of the collaboration agreement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	ions_TermOfCollaborationAgreement
Namespace Prefix:	ions_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The amount of the upfront payment allocated to delivery of the active pharmaceutical ingredient (API) for the drug under the collaboration agreement.

No definition available.

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

The amount of the upfront payment allocated to the exclusive license of the drug under the collaboration agreement.

No definition available.

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

The amount of the upfront payment allocated to ongoing development services for the drug under the collaboration agreement.

No definition available.

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

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

No definition available.

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

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.

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=65893310&loc=d3e214044-122780

Reference 2: 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.3)
-URI http://asc.fasb.org/extlink&oid=65893310&loc=d3e214044-122780

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

- References

No definition available.

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

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).

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=63488584&loc=d3e20235-122688

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

Name:	us-gaap_MajorCustomersAxis=ions_AstraZenecaPLCBiogenIncAndJanssenBiotechIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_TypeOfArrangementAxis=ions_CollaborativeArrangementAndLicensingAgreementEnteredIntoInMay2015Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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

Name:	us-gaap_TypeOfArrangementAxis=ions_CollaborativeArrangementAndLicensingAgreementEnteredIntoInJanuary2012Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_TypeOfArrangementAxis=ions_CollaborativeArrangementAndLicensingAgreementEnteredIntoInJune2012Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_TypeOfArrangementAxis=ions_CollaborativeArrangementAndLicensingAgreementEnteredIntoInDecember2012Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: