XML 43 R33.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Loss Per Common Share - Additional Information (Detail) - USD ($) $ in Thousands, shares in Millions |  | 3 Months Ended | 6 Months Ended |
--- | --- | --- | --- | ---
May 02, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Dec. 31, 2017
Loss Per Common Share [Line Items] |  |  |  |  |  |
Convertible senior notes principal amount |  | $ 517,500 |  | $ 517,500 |  | $ 517,500
2.25% Convertible Senior Notes due 2024 |  |  |  |  |  |
Loss Per Common Share [Line Items] |  |  |  |  |  |
Common share equivalents excluded from computation of earnings per share | 6.8 |  |  |  |  |
Convertible senior notes principal amount | $ 517,500 |  |  |  |  |
Stock Options, Unvested RSUs and PRSUs |  |  |  |  |  |
Loss Per Common Share [Line Items] |  |  |  |  |  |
Common share equivalents excluded from computation of earnings per share |  | 7.5 | 5.0 | 7.5 | 5.0 |

X
- Definition Loss per common share. + References No definition available. + Details
Name: | nbix_LossPerCommonShareLineItems
Namespace Prefix: | nbix_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 + Details
Name: | us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=nbix_SeniorConvertibleNotesTwoPointTwoFivePercentDueInMayTwoThousandTwentyFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis=nbix_StockOptionsUnvestedRestrictedStockUnitsAndPerformanceBasedRestrictedStockUnitsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |