Name:	isis_CollaborativeArrangementAndLicensingAgreementAbstract
Namespace Prefix:	isis_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Cumulative amount of milestone payments earned and received under the collaborative arrangement as of the end of the reporting period.

+ References

No definition available.

+ Details

Name:	isis_CollaborativeArrangementPaymentsEarnedAndReceivedThroughoutArrangement
Namespace Prefix:	isis_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the maximum amount of payments receivable under the agreement.

+ References

No definition available.

+ Details

Name:	isis_MaximumAmountOfPaymentsReceivable
Namespace Prefix:	isis_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the next prospective milestone payment to be earned.

+ References

No definition available.

+ Details

Name:	isis_ProspectiveMilestonePayment
Namespace Prefix:	isis_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

The amount of consideration recognized during the period for the milestone or milestones.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 28

-Section 50

-Paragraph 2

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=19771982&loc=SL6892177-166501

+ Details

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

Collaborative Arrangements and Licensing Agreements, Biogen Idec (ISIS-DMPK) (Details) (Biogen Idec [Member], Agreement entered into in June 2012 [Member], ISIS-DMPK [Member], USD $)	1 Months Ended
	Jun. 30, 2014	Jun. 30, 2012	Sep. 30, 2014
Collaborative Arrangement and Licensing Agreement [Abstract]
Upfront fee recorded as deferred revenue		$ 12,000,000
Milestone payment earned	14,000,000
Next prospective milestone			35,000,000
License fee and substantive milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payment receivable			259,000,000
Cumulative milestone payments earned under collaborative arrangement at period end			24,000,000
Development milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payment receivable			35,000,000
Regulatory milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payment receivable			$ 130,000,000