Contingent payments receivable based on development events.

No definition available.

Name:	nktr_ContingentPaymentsReceivableBasedOnDevelopmentEvents
Namespace Prefix:	nktr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Expected consideration.

+ References

No definition available.

+ Details

Name:	nktr_ExpectedConsideration
Namespace Prefix:	nktr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

License and collaboration agreements potential payments for development milestones.

+ References

No definition available.

+ Details

Name:	nktr_LicenseAndCollaborationAgreementsPotentialPaymentsForDevelopmentMilestones
Namespace Prefix:	nktr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Performance milestone used to reimburse clinical trial costs.

+ References

No definition available.

+ Details

Name:	nktr_PerformanceMilestoneUsedToReimburseClinicalTrialCosts
Namespace Prefix:	nktr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Substantive milestone revenue.

+ References

No definition available.

+ Details

Name:	nktr_SubstantiveMilestoneRevenue
Namespace Prefix:	nktr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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 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=6600647&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_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=6600647&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

- Details

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

- Definition

Revenue earned during the period relating to consideration received from another party for the right to use, but not own, certain of the entity's intangible assets. Licensing arrangements include, but are not limited to, rights to use a patent, copyright, technology, manufacturing process, software or trademark. Licensing fees are generally, but not always, fixed as to amount and not dependent upon the revenue generated by the licensing party. An entity may receive licensing fees for licenses that also generate royalty payments to the entity.

+ 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(e))

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

+ Details

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

License and Collaboration Agreements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified		9 Months Ended	12 Months Ended	2 Months Ended	9 Months Ended	3 Months Ended		9 Months Ended	12 Months Ended				3 Months Ended		9 Months Ended	2 Months Ended	9 Months Ended	1 Months Ended			3 Months Ended
	Sep. 30, 2012	Sep. 30, 2012 Baxter Healthcare [Member]	Dec. 31, 2005 Baxter Healthcare [Member]	Dec. 31, 2009 Roche [Member] License Option [Member]	Sep. 30, 2012 Roche [Member] Performance milestone payments [Member]	Dec. 31, 2010 Amgen Inc [Member]	Sep. 30, 2012 Amgen Inc [Member]	Sep. 30, 2012 Bayer Healthcare LLC [Member]	Dec. 31, 2007 Bayer Healthcare LLC [Member] Up-front payment arrangement [Member]	Dec. 31, 2007 Bayer Healthcare LLC [Member] Performance milestone payments [Member]	Sep. 29, 2012 AstraZeneca AB [Member]	Sep. 30, 2012 Hemophilia [Member] Baxter Healthcare [Member]	Jun. 30, 2012 Hemophilia B [Member]	Sep. 30, 2012 PEGASYS [Member] Roche [Member]	Sep. 30, 2012 MIRCERA [Member] Roche [Member]	Feb. 29, 2012 MIRCERA [Member] Roche [Member] Up-front payment arrangement [Member]	Sep. 30, 2012 MIRCERA [Member] Roche [Member] Up-front payment arrangement [Member]	Feb. 29, 2012 MIRCERA [Member] Roche [Member] Performance milestone payments [Member]	Sep. 30, 2012 Omontys [Member] Affymax Inc [Member]	Mar. 27, 2012 Omontys [Member] Affymax Inc [Member]	Dec. 31, 2009 NKTR-118 and NKTR-119 [Member] AstraZeneca AB [Member] Up-front payment arrangement [Member]	Sep. 29, 2012 NKTR-118 [Member]	Sep. 30, 2012 NKTR-118 [Member] AstraZeneca AB [Member]	Sep. 30, 2012 NKTR-119 [Member] AstraZeneca AB [Member]
Deferred Revenue Arrangement [Line Items]
Potential future payments for development milestones	$ 161.1							$ 60.0				$ 28.0
Contingent payments receivable based on development events to be pursued and completed solely by others											95.0											140.0	235.0	75.0
Received upfront and milestone payments		5.0	4.0	31.0		50.0			40.0	20.0						5.0	16.0				125.0
Deferred Revenue							40.4	25.2				1.4		16.7	13.7				7.3
Revenue recognized as contractual obligations completed													3.9		2.3
Expected consideration					11.0										27.0			22.0
Substantive milestone revenue																				2.0
Performance milestone to be used to reimburse future clinical trial costs								$ 10.0