XML 70 R53.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Deferred tax assets, valuation allowance	$ 346,000	$ 335,200
Research and development tax credit carry forwards	$ 71,900	62,200
Percentage of uncertain tax positions likelihood of being sustained	50.00%
Increases related to current year tax positions	$ 9,519	$ 11,726	$ 3,291
Unrecognized tax benefits that would affect effective tax rate	57,900
Federal
Income Taxes [Line Items]
Operating loss carry forward, net	$ 816,200
Operating loss carry forward beginning expiration year	2024
Research and development tax credit carry forwards	$ 73,200
Federal | R&D
Income Taxes [Line Items]
Tax credit carry forwards beginning expiration year	2019
State and Local Jurisdiction
Income Taxes [Line Items]
Operating loss carry forward, net	$ 359,800
Research and development tax credit carry forwards	$ 47,500
State and Local Jurisdiction | California
Income Taxes [Line Items]
Operating loss carry forward beginning expiration year	2028
State and Local Jurisdiction | Other States
Income Taxes [Line Items]
Operating loss carry forward beginning expiration year	2026

X

- Definition

Income Taxes [Line Items]

+ References

No definition available.

+ Details

Name:	nbix_IncomeTaxesLineItems
Namespace Prefix:	nbix_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Operating loss carryforwards, beginning expiration year.

+ References

No definition available.

+ Details

Name:	nbix_OperatingLossCarryforwardsBeginningExpirationYear
Namespace Prefix:	nbix_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of uncertain tax positions likelihood of being sustained.

+ References

No definition available.

+ Details

Name:	nbix_PercentageOfUncertainTaxPositionsLikelihoodOfBeingSustained
Namespace Prefix:	nbix_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tax credit carryforward, beginning expiration year.

+ References

No definition available.

+ Details

Name:	nbix_TaxCreditCarryforwardBeginningExpirationYear
Namespace Prefix:	nbix_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible research tax credit carryforwards.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32632-109319

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32621-109319

+ Details

Name:	us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319

+ Details

Name:	us-gaap_DeferredTaxAssetsValuationAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319

+ Details

Name:	us-gaap_OperatingLossCarryforwards
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

+ Details

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

X

- Definition

The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

+ Details

Name:	us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=us-gaap_InternalRevenueServiceIRSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_TaxCreditCarryforwardAxis=us-gaap_ResearchMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=us-gaap_StateAndLocalJurisdictionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=stpr_CA
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=nbix_OtherStatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: