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

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

+ References

No definition available.

+ Details

Name:	isis_MaximumAmountOfPaymentReceivablePerDrug
Namespace Prefix:	isis_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

The number of development candidates that must be generated for the brain shuttle program by a mutually agreed deadline to prevent termination by either party under the collaborative arrangement.

+ References

No definition available.

+ Details

Name:	isis_NumberOfDevelopmentCandidatesThatMustBeGeneratedForBrainShuttleProgram
Namespace Prefix:	isis_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- 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 as of balance sheet date. Deferred revenue represents collections of cash or other assets 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 SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 13

-Section A

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.4(a).Q1 Response)

-URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780

+ Details

Name:	us-gaap_DeferredRevenue
Namespace Prefix:	us-gaap_
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

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

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

Collaborative Arrangements and Licensing Agreements, Roche (Details) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		1 Months Ended							9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Roche [Member] Collaborations and Licensing Agreements [Member]	Sep. 30, 2013 Roche [Member] Collaborations and Licensing Agreements [Member]	Sep. 30, 2014 Roche [Member] Collaborations and Licensing Agreements [Member]	Sep. 30, 2013 Roche [Member] Collaborations and Licensing Agreements [Member]	Apr. 30, 2013 Roche [Member] Agreement entered into in April 2013 [Member]	Sep. 30, 2014 Roche [Member] Agreement entered into in April 2013 [Member]	Sep. 30, 2014 Roche [Member] Agreement entered into in April 2013 [Member] Development, regulatory and commercial milestones [Member]	Sep. 30, 2014 Roche [Member] Agreement entered into in April 2013 [Member] HTT [Member] License fee and substantive milestones [Member]	Sep. 30, 2014 Roche [Member] Agreement entered into in April 2013 [Member] HTT [Member] Development milestones [Member]	Sep. 30, 2014 Roche [Member] Agreement entered into in April 2013 [Member] HTT [Member] Regulatory milestones [Member]	Sep. 30, 2014 Roche [Member] Agreement entered into in April 2013 [Member] HTT [Member] Commercialization milestones [Member]	Sep. 30, 2014 Roche [Member] Agreement entered into in April 2013 [Member] Brain Shuttle [Member] Candidate	Sep. 30, 2014 Roche [Member] Agreement entered into in April 2013 [Member] Brain Shuttle [Member] Commercialization milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Upfront fee recorded as deferred revenue									$ 30,000,000
Maximum amount of payment receivable												362,000,000	67,000,000	170,000,000	80,000,000		50,000,000
Maximum amount of payment receivable per drug											136,500,000
Next prospective milestone										22,000,000
Number of development candidates that must be generated for brain shuttle program																1
Revenue earned	44,063,000	23,585,000	129,300,000	105,036,000	2,300,000	1,900,000	6,700,000	3,200,000
Deferred revenue					$ 19,000,000		$ 19,000,000