XML 63 R49.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Stockholders' Equity - Additional Information (Detail) - USD ($) |  |  |  | 12 Months Ended
--- | --- | --- | --- | ---
Jun. 26, 2018 | Apr. 03, 2018 | Oct. 24, 2016 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Class of Stock [Line Items] |  |  |  |  |  |
Proceeds from sale of common stock |  |  | $ 189,700,000 |  |  |
Stock issued during period subject to lock-up and stand-still provisions period |  | 5 years |  |  |  |
Number of shares to be issued upon exercise of outstanding options or vesting of RSUs |  |  |  | 19,250,000 |  |
Number of shares available for issuance under equity compensation plans |  |  |  | 12,690,000 |  |
Common stock, shares authorized |  |  |  | 300,000,000 | 300,000,000 |
Maximum 401(k) per employee, percentage of annual salary |  |  |  | 60.00% |  |
Matching 401(k) employer contribution, maximum amount |  |  |  | $ 6,000 |  |
Compensation expense in connection with 401(k) retirement plan |  |  |  | $ 2,800,000 | $ 1,600,000 | $ 1,100,000
Change in control severance payment period for executives |  |  |  | 12 months |  |
Change in control severance payment period for employees |  |  |  | 6 months |  |
Change in control cash severance payment for chief executive officer |  |  |  | 24 months base salary plus annual target incentive pay |  |
Employee Stock Purchase Plan [Member] |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Common stock, shares authorized |  |  |  | 2,500,000 |  |
Percentage of purchase price of stock |  |  |  | 85.00% |  |
2017 Performance Incentive Plan [Member] |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Number of common stock shares available for stock options grants |  |  |  | 8,300,000 |  |
Number of additional shares available for award grants | 10,900,000 |  |  |  |  |
Share-based compensation plan's share limit reduction for every one restricted stock unit granted |  |  |  | 1.5 |  |
Stock options term under equity incentive plans |  |  |  | 8 years |  |
2017 Performance Incentive Plan [Member] | Shares of Common Stock Underlying Outstanding Stock Options [Member] | Employee [Member] |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Service period for stock-based compensation award granted |  |  |  | 4 years |  |
2017 Performance Incentive Plan [Member] | Shares of Common Stock Underlying Outstanding Stock Options [Member] | Director [Member] |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Service period for stock-based compensation award granted |  |  |  | 1 year |  |
2017 Performance Incentive Plan [Member] | Restricted Stock Units (RSU) [Member] | Employee [Member] |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Service period for stock-based compensation award granted |  |  |  | 3 years |  |
2017 Performance Incentive Plan [Member] | Restricted Stock Units (RSU) [Member] | Director [Member] |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Service period for stock-based compensation award granted |  |  |  | 1 year |  |
Common Shares [Member] |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Sale of common stock, Shares |  | 8,284,600 | 14,950,000 |  |  | 14,950,000
Underwriting commissions and discounts |  |  | $ 12,100,000 |  |  |
Legal, accounting fees, filing fees and other offering expenses |  |  | $ 400,000 |  |  |
Common stock, shares reserved for issuance in equity compensation plans |  |  |  | 31,940,416 |  |

X
- Definition Change in control cash severance payment for to chief executive officer. + References No definition available. + Details
Name: | nktr_ChangeInControlCashSeverancePaymentForToChiefExecutiveOfficer
Namespace Prefix: | nktr_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Change in control severance payment period for employees. + References No definition available. + Details
Name: | nktr_ChangeInControlSeverancePaymentPeriodForEmployees
Namespace Prefix: | nktr_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Change in control severance payment period for executives. + References No definition available. + Details
Name: | nktr_ChangeInControlSeverancePaymentPeriodForExecutives
Namespace Prefix: | nktr_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of securities remaining available for issuance under equity compensation plans. + References No definition available. + Details
Name: | nktr_NumberOfSecuritiesAvailableForIssuanceUnderEquityCompensationPlans
Namespace Prefix: | nktr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of purchase price of stock. + References No definition available. + Details
Name: | nktr_PercentageOfPurchasePriceOfStock
Namespace Prefix: | nktr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share based compensation arrangement by share based payment award options and restricted stock units outstanding. + References No definition available. + Details
Name: | nktr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndRestrictedStockUnitsOutstanding
Namespace Prefix: | nktr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Share based compensation plan's share limit for every one share. + References No definition available. + Details
Name: | nktr_ShareBasedCompensationPlansShareLimitForEveryOneShare
Namespace Prefix: | nktr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Stock issued during period subject to lock-up and stand-still provisions period. + References No definition available. + Details
Name: | nktr_StockIssuedDuringPeriodSubjectToLockUpAndStandStillProvisionsPeriod
Namespace Prefix: | nktr_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Underwriters commissions and discount. + References No definition available. + Details
Name: | nktr_UnderwritersCommissionsAndDiscount
Namespace Prefix: | nktr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ClassOfStockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate number of common shares reserved for future issuance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The maximum number of common shares permitted to be issued by an entity's charter and bylaws. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of contributions made by employer into fund established for purposes of making future disbursement to individual in accordance with deferred compensation arrangement. + References No definition available. + Details
Name: | us-gaap_DeferredCompensationArrangementWithIndividualContributionsByEmployer
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of cost for defined contribution plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
Name: | us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash outflow for cost incurred directly with the issuance of an equity security. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3291-108585 + Details
Name: | us-gaap_PaymentsOfStockIssuanceCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow from the additional capital contribution to the entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromIssuanceOfCommonStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of additional shares authorized for issuance under an established share-based compensation plan. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of new stock issued during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=us-gaap_EmployeeStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=nktr_TwoThousandSeventeenPerformanceIncentivePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TitleOfIndividualAxis=nktr_EmployeeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TitleOfIndividualAxis=us-gaap_DirectorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |