<?xml version='1.0' encoding='UTF-8'?>
<FilingSummary>
  <Version>3.7.0.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>185</ContextCount>
  <ElementCount>249</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>48</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>10</UnitCount>
  <MyReports>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>100000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>100010 - Statement - Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/StatementBalanceSheets</Role>
      <ShortName>Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>100020 - Statement - Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/StatementBalanceSheetsParenthetical</Role>
      <ShortName>Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>100030 - Statement - Statements of Operations and Comprehensive Loss (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/StatementStatementsOfOperationsAndComprehensiveLossUnaudited</Role>
      <ShortName>Statements of Operations and Comprehensive Loss (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>100040 - Statement - Statements of Cash Flows (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/StatementStatementsOfCashFlowsUnaudited</Role>
      <ShortName>Statements of Cash Flows (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>100050 - Disclosure - Organization, Liquidity and Management's Plan, and Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureOrganizationLiquidityAndManagementSPlanAndSummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Organization, Liquidity and Management's Plan, and Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>100060 - Disclosure - Investments in Marketable Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureInvestmentsInMarketableSecurities</Role>
      <ShortName>Investments in Marketable Securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>100070 - Disclosure - Fair Value of Financial Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureFairValueOfFinancialInstruments</Role>
      <ShortName>Fair Value of Financial Instruments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>100080 - Disclosure - Convertible Notes Payable</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureConvertibleNotesPayable</Role>
      <ShortName>Convertible Notes Payable</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>100090 - Disclosure - Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureStockholdersEquity</Role>
      <ShortName>Stockholders' Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>100100 - Disclosure - Stock-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureStockBasedCompensation</Role>
      <ShortName>Stock-Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>100110 - Disclosure - Warrants</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureWarrants</Role>
      <ShortName>Warrants</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>100120 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>100130 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureSubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>100140 - Disclosure - Organization, Liquidity and Management's Plan, and Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureOrganizationLiquidityAndManagementSPlanAndSummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Organization, Liquidity and Management's Plan, and Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureOrganizationLiquidityAndManagementSPlanAndSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>15</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>100150 - Disclosure - Organization, Liquidity and Management's Plan, and Summary of Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureOrganizationLiquidityAndManagementSPlanAndSummaryOfSignificantAccountingPoliciesTables</Role>
      <ShortName>Organization, Liquidity and Management's Plan, and Summary of Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureOrganizationLiquidityAndManagementSPlanAndSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>16</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>100160 - Disclosure - Investments in Marketable Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureInvestmentsInMarketableSecuritiesTables</Role>
      <ShortName>Investments in Marketable Securities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureInvestmentsInMarketableSecurities</ParentRole>
      <Position>17</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>100170 - Disclosure - Fair Value of Financial Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsTables</Role>
      <ShortName>Fair Value of Financial Instruments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureFairValueOfFinancialInstruments</ParentRole>
      <Position>18</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>100180 - Disclosure - Convertible Notes Payable (Tables)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureConvertibleNotesPayableTables</Role>
      <ShortName>Convertible Notes Payable (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureConvertibleNotesPayable</ParentRole>
      <Position>19</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>100190 - Disclosure - Stock-Based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureStockBasedCompensationTables</Role>
      <ShortName>Stock-Based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureStockBasedCompensation</ParentRole>
      <Position>20</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>100200 - Disclosure - Commitments and Contingencies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureCommitmentsAndContingenciesTables</Role>
      <ShortName>Commitments and Contingencies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureCommitmentsAndContingencies</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>100210 - Disclosure - Organization, Liquidity and Management's Plan, and Summary of Significant Accounting Policies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureOrganizationLiquidityAndManagementSPlanAndSummaryOfSignificantAccountingPoliciesAdditionalInformationDetail</Role>
      <ShortName>Organization, Liquidity and Management's Plan, and Summary of Significant Accounting Policies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>100220 - Disclosure - Organization, Liquidity and Management's Plan, and Summary of Significant Accounting Policies - Schedule of Computation of Basic and Diluted Net Loss per Common Share (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureOrganizationLiquidityAndManagementSPlanAndSummaryOfSignificantAccountingPoliciesScheduleOfComputationOfBasicAndDilutedNetLossPerCommonShareDetail</Role>
      <ShortName>Organization, Liquidity and Management's Plan, and Summary of Significant Accounting Policies - Schedule of Computation of Basic and Diluted Net Loss per Common Share (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>100230 - Disclosure - Organization, Liquidity and Management's Plan, and Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss per Share (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureOrganizationLiquidityAndManagementSPlanAndSummaryOfSignificantAccountingPoliciesScheduleOfPotentiallyDilutiveSecuritiesNotIncludedInCalculationOfDilutedNetLossPerShareDetail</Role>
      <ShortName>Organization, Liquidity and Management's Plan, and Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss per Share (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>100240 - Disclosure - Investments in Marketable Securities - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureInvestmentsInMarketableSecuritiesAdditionalInformationDetail</Role>
      <ShortName>Investments in Marketable Securities - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>100250 - Disclosure - Investments in Marketable Securities - Summary of Investments Classified As Available-For-Sale Securities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureInvestmentsInMarketableSecuritiesSummaryOfInvestmentsClassifiedAsAvailableForSaleSecuritiesDetail</Role>
      <ShortName>Investments in Marketable Securities - Summary of Investments Classified As Available-For-Sale Securities (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>100260 - Disclosure - Investments in Marketable Securities - Summary of Investments Classified As Available-For-Sale Securities (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureInvestmentsInMarketableSecuritiesSummaryOfInvestmentsClassifiedAsAvailableForSaleSecuritiesParentheticalDetail</Role>
      <ShortName>Investments in Marketable Securities - Summary of Investments Classified As Available-For-Sale Securities (Parenthetical) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>100270 - Disclosure - Fair Value of Financial Instruments - Summary of Fair Values of Financial Instruments (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsSummaryOfFairValuesOfFinancialInstrumentsDetail</Role>
      <ShortName>Fair Value of Financial Instruments - Summary of Fair Values of Financial Instruments (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>100290 - Disclosure - Fair Value of Financial Instruments - Summary of Changes in Debt Conversion Feature Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsSummaryOfChangesInDebtConversionFeatureLiabilitiesMeasuredAtFairValueOnRecurringBasisUsingSignificantUnobservableInputsDetail</Role>
      <ShortName>Fair Value of Financial Instruments - Summary of Changes in Debt Conversion Feature Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>100300 - Disclosure - Fair Value of Financial Instruments - Schedule of Valuation Techniques and Significant Unobservable Inputs Used to Determine Fair Value of Significant Level 3 Liabilities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsScheduleOfValuationTechniquesAndSignificantUnobservableInputsUsedToDetermineFairValueOfSignificantLevel3LiabilitiesDetail</Role>
      <ShortName>Fair Value of Financial Instruments - Schedule of Valuation Techniques and Significant Unobservable Inputs Used to Determine Fair Value of Significant Level 3 Liabilities (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>100310 - Disclosure - Convertible Notes Payable - Schedule of Convertible Notes Payable (Detail)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureConvertibleNotesPayableScheduleOfConvertibleNotesPayableDetail</Role>
      <ShortName>Convertible Notes Payable - Schedule of Convertible Notes Payable (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>100320 - Disclosure - Convertible Notes Payable - Schedule of Convertible Notes Payable (Parenthetical) (Detail)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureConvertibleNotesPayableScheduleOfConvertibleNotesPayableParentheticalDetail</Role>
      <ShortName>Convertible Notes Payable - Schedule of Convertible Notes Payable (Parenthetical) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>100330 - Disclosure - Convertible Notes Payable - Additional Information (Detail)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureConvertibleNotesPayableAdditionalInformationDetail</Role>
      <ShortName>Convertible Notes Payable - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>100340 - Disclosure - Stockholders' Equity - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureStockholdersEquityAdditionalInformationDetail</Role>
      <ShortName>Stockholders' Equity - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>100350 - Disclosure - Stock-Based Compensation - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureStockBasedCompensationAdditionalInformationDetail</Role>
      <ShortName>Stock-Based Compensation - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>100360 - Disclosure - Stock-Based Compensation - Summary of Stock-based Compensation Expense Recognized (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureStockBasedCompensationSummaryOfStockBasedCompensationExpenseRecognizedDetail</Role>
      <ShortName>Stock-Based Compensation - Summary of Stock-based Compensation Expense Recognized (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>100370 - Disclosure - Stock-Based Compensation - Schedule of Unrecognized Stock-based Compensation Expense, Net of Estimated Forfeitures, by Type of Award and Weighted-average Recognition Period (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureStockBasedCompensationScheduleOfUnrecognizedStockBasedCompensationExpenseNetOfEstimatedForfeituresByTypeOfAwardAndWeightedAverageRecognitionPeriodDetail</Role>
      <ShortName>Stock-Based Compensation - Schedule of Unrecognized Stock-based Compensation Expense, Net of Estimated Forfeitures, by Type of Award and Weighted-average Recognition Period (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>100380 - Disclosure - Stock-Based Compensation - Summary of Restricted Stock Activity (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureStockBasedCompensationSummaryOfRestrictedStockActivityDetail</Role>
      <ShortName>Stock-Based Compensation - Summary of Restricted Stock Activity (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>100390 - Disclosure - Stock-Based Compensation - Summary of Restricted Stock Units Activity (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureStockBasedCompensationSummaryOfRestrictedStockUnitsActivityDetail</Role>
      <ShortName>Stock-Based Compensation - Summary of Restricted Stock Units Activity (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>100400 - Disclosure - Stock-Based Compensation - Summary of Stock Option Activity (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureStockBasedCompensationSummaryOfStockOptionActivityDetail</Role>
      <ShortName>Stock-Based Compensation - Summary of Stock Option Activity (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>100410 - Disclosure - Stock-Based Compensation - Schedule of Weighted Average Assumptions using Black-Scholes Option Pricing Model (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureStockBasedCompensationScheduleOfWeightedAverageAssumptionsUsingBlackScholesOptionPricingModelDetail</Role>
      <ShortName>Stock-Based Compensation - Schedule of Weighted Average Assumptions using Black-Scholes Option Pricing Model (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>100420 - Disclosure - Warrants - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureWarrantsAdditionalInformationDetail</Role>
      <ShortName>Warrants - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>100430 - Disclosure - Commitments and Contingencies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureCommitmentsAndContingenciesAdditionalInformationDetail</Role>
      <ShortName>Commitments and Contingencies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>100440 - Disclosure - Commitments and Contingencies - Summary of Future Minimum Payments for Sublease (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureCommitmentsAndContingenciesSummaryOfFutureMinimumPaymentsForSubleaseDetail</Role>
      <ShortName>Commitments and Contingencies - Summary of Future Minimum Payments for Sublease (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="vktx-20170630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>100450 - Disclosure - Subsequent Events - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.vikingtherapeutics.com/20170630/taxonomy/role/DisclosureSubsequentEventsAdditionalInformationDetail</Role>
      <ShortName>Subsequent Events - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>vktx-20170630.xml</File>
    <File>vktx-20170630.xsd</File>
    <File>vktx-20170630_cal.xml</File>
    <File>vktx-20170630_def.xml</File>
    <File>vktx-20170630_lab.xml</File>
    <File>vktx-20170630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies/>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
