<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>236</ContextCount>
  <ElementCount>442</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>75</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>4</UnitCount>
  <MyReports>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001000 - Document - Document And Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document And Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001000 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CondensedConsolidatedStatementsOfIncomeUnaudited</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1002000 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CondensedConsolidatedStatementsOfComprehensiveIncomeUnaudited</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1002501 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CondensedConsolidatedStatementsOfComprehensiveIncomeParentheticals</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parentheticals)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1003000 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CondensedConsolidatedBalanceSheets</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1003501 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CondensedConsolidatedBalanceSheetsParentheticals</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS (Parentheticals)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1004000 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CondensedConsolidatedStatementsOfCashFlowsUnaudited</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>1005000 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY Statement</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CondensedConsolidatedStatementsOfStockholdersEquityStatement</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY Statement</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2102100 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/SummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2103100 - Disclosure - Net Income per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/NetIncomePerShare</Role>
      <ShortName>Net Income per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2104100 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/FairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2105100 - Disclosure - Cash Equivalents and Investments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CashEquivalentsAndInvestments</Role>
      <ShortName>Cash Equivalents and Investments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2107100 - Disclosure - Notes Receivable and Other Long-term Receivables</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/NotesReceivableAndOtherLongTermReceivables</Role>
      <ShortName>Notes Receivable and Other Long-term Receivables</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2111100 - Disclosure - Accrued Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/AccruedLiabilities</Role>
      <ShortName>Accrued Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2112100 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2113100 - Disclosure - Convertible Notes</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/ConvertibleNotes</Role>
      <ShortName>Convertible Notes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2115100 - Disclosure - Other Long-Term Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/OtherLongTermLiabilities</Role>
      <ShortName>Other Long-Term Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2116100 - Disclosure - Stock-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/StockBasedCompensation</Role>
      <ShortName>Stock-Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2117100 - Disclosure - Cash Dividends</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CashDividends</Role>
      <ShortName>Cash Dividends</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2118100 - Disclosure - Customer Concentration</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CustomerConcentration</Role>
      <ShortName>Customer Concentration</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2119100 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2126100 - Disclosure - Intangibles and Goodwill (Notes)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/IntangiblesAndGoodwillNotes</Role>
      <ShortName>Intangibles and Goodwill (Notes)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2127100 - Disclosure - Segment Information (Notes)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/SegmentInformationNotes</Role>
      <ShortName>Segment Information (Notes)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2128100 - Disclosure - Inventory (Notes)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/InventoryNotes</Role>
      <ShortName>Inventory (Notes)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2129100 - Disclosure - Stockholders' Equity (Notes)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/StockholdersEquityNotes</Role>
      <ShortName>Stockholders' Equity (Notes)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2130100 - Disclosure - Revenue from Contracts with Customers (Notes)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/RevenueFromContractsWithCustomersNotes</Role>
      <ShortName>Revenue from Contracts with Customers (Notes)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2132100 - Disclosure - Leases (Notes)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/LeasesNotes</Role>
      <ShortName>Leases (Notes)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2133100 - Disclosure - Investment in Evofem (Notes)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/InvestmentInEvofemNotes</Role>
      <ShortName>Investment in Evofem (Notes)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2134100 - Disclosure - Assets Held for Sale (Notes)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/AssetsHeldForSaleNotes</Role>
      <ShortName>Assets Held for Sale (Notes)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2202201 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/SummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.pdl.com/role/SummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2303301 - Disclosure - Net Income per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/NetIncomePerShareTables</Role>
      <ShortName>Net Income per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pdl.com/role/NetIncomePerShare</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2304301 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/FairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pdl.com/role/FairValueMeasurements</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2305301 - Disclosure - Cash Equivalents and Investments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CashEquivalentsAndInvestmentsTables</Role>
      <ShortName>Cash Equivalents and Investments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pdl.com/role/CashEquivalentsAndInvestments</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2311301 - Disclosure - Accrued Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/AccruedLiabilitiesTables</Role>
      <ShortName>Accrued Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pdl.com/role/AccruedLiabilities</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2313301 - Disclosure - Convertible Notes (Tables)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/ConvertibleNotesTables</Role>
      <ShortName>Convertible Notes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pdl.com/role/ConvertibleNotes</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2315301 - Disclosure - Other Long-Term Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/OtherLongTermLiabilitiesTables</Role>
      <ShortName>Other Long-Term Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pdl.com/role/OtherLongTermLiabilities</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2318301 - Disclosure - Customer Concentration (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CustomerConcentrationTables</Role>
      <ShortName>Customer Concentration (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pdl.com/role/CustomerConcentration</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2326301 - Disclosure - Intangibles and Goodwill (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/IntangiblesAndGoodwillTables</Role>
      <ShortName>Intangibles and Goodwill (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pdl.com/role/IntangiblesAndGoodwillNotes</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2326302 - Disclosure - Intangibles and Goodwill Remaining Amortization Expense (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/IntangiblesAndGoodwillRemainingAmortizationExpenseTables</Role>
      <ShortName>Intangibles and Goodwill Remaining Amortization Expense (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2327301 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/SegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pdl.com/role/SegmentInformationNotes</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2328301 - Disclosure - Inventory (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/InventoryTables</Role>
      <ShortName>Inventory (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pdl.com/role/InventoryNotes</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2330301 - Disclosure - Revenue from Contracts with Customers (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/RevenueFromContractsWithCustomersTables</Role>
      <ShortName>Revenue from Contracts with Customers (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pdl.com/role/RevenueFromContractsWithCustomersNotes</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2332301 - Disclosure - Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/LeasesTables</Role>
      <ShortName>Leases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pdl.com/role/LeasesNotes</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2333301 - Disclosure - Investment in Evofem (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/InvestmentInEvofemTables</Role>
      <ShortName>Investment in Evofem (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.pdl.com/role/InvestmentInEvofemNotes</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2402403 - Disclosure - Summary of Significant Accounting Policies (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/SummaryOfSignificantAccountingPoliciesNarrativeDetail</Role>
      <ShortName>Summary of Significant Accounting Policies (Narrative) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/SummaryOfSignificantAccountingPoliciesPolicies</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2403402 - Disclosure - Net Income per Share (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/NetIncomePerShareNarrativeDetail</Role>
      <ShortName>Net Income per Share (Narrative) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/NetIncomePerShareTables</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2403403 - Disclosure - Net Income per Share (Net Income Per Basic and Diluted Share) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/NetIncomePerShareNetIncomePerBasicAndDilutedShareDetail</Role>
      <ShortName>Net Income per Share (Net Income Per Basic and Diluted Share) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/NetIncomePerShareTables</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2404402 - Disclosure - Fair Value Measurements (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/FairValueMeasurementsNarrativeDetail</Role>
      <ShortName>Fair Value Measurements (Narrative) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/FairValueMeasurementsTables</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2404403 - Disclosure - Fair Value Measurements (Financial Instruments Measured at Fair Value on a Recurring Basis) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/FairValueMeasurementsFinancialInstrumentsMeasuredAtFairValueOnRecurringBasisDetail</Role>
      <ShortName>Fair Value Measurements (Financial Instruments Measured at Fair Value on a Recurring Basis) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/FairValueMeasurementsTables</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2404404 - Disclosure - Fair Value Measurements (Schedule of Fair Value of Assets and Liabilities not Subject to Fair Value Recognition) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/FairValueMeasurementsScheduleOfFairValueOfAssetsAndLiabilitiesNotSubjectToFairValueRecognitionDetail</Role>
      <ShortName>Fair Value Measurements (Schedule of Fair Value of Assets and Liabilities not Subject to Fair Value Recognition) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/FairValueMeasurementsTables</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2404405 - Disclosure - Fair Value Measurements Level 3 Unobservable Input Reconciliation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/FairValueMeasurementsLevel3UnobservableInputReconciliationDetails</Role>
      <ShortName>Fair Value Measurements Level 3 Unobservable Input Reconciliation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2405402 - Disclosure - Cash Equivalents and Investments (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CashEquivalentsAndInvestmentsNarrativeDetail</Role>
      <ShortName>Cash Equivalents and Investments (Narrative) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/CashEquivalentsAndInvestmentsTables</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2405403 - Disclosure - Cash Equivalents and Investments (Summary of Cash and Available-For-Sale Securities) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CashEquivalentsAndInvestmentsSummaryOfCashAndAvailableForSaleSecuritiesDetail</Role>
      <ShortName>Cash Equivalents and Investments (Summary of Cash and Available-For-Sale Securities) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/CashEquivalentsAndInvestmentsTables</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2407401 - Disclosure - Notes Receivable and Other Long-term Receivables (Narrative) (Detail)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/NotesReceivableAndOtherLongTermReceivablesNarrativeDetail</Role>
      <ShortName>Notes Receivable and Other Long-term Receivables (Narrative) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/NotesReceivableAndOtherLongTermReceivables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2411403 - Disclosure - Accrued Liabilities (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/AccruedLiabilitiesNarrativeDetail</Role>
      <ShortName>Accrued Liabilities (Narrative) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/AccruedLiabilitiesTables</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2411404 - Disclosure - Accrued Liabilities (Accrued Liabilities) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/AccruedLiabilitiesAccruedLiabilitiesDetail</Role>
      <ShortName>Accrued Liabilities (Accrued Liabilities) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/AccruedLiabilitiesTables</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2412402 - Disclosure - Commitments and Contingencies (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CommitmentsAndContingenciesNarrativeDetail</Role>
      <ShortName>Commitments and Contingencies (Narrative) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/CommitmentsAndContingencies</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>2413402 - Disclosure - Convertible Notes (Narrative) (Detail)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/ConvertibleNotesNarrativeDetail</Role>
      <ShortName>Convertible Notes (Narrative) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/ConvertibleNotesTables</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>2413403 - Disclosure - Convertible Notes (Summary of Convertible Notes) (Detail)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/ConvertibleNotesSummaryOfConvertibleNotesDetail</Role>
      <ShortName>Convertible Notes (Summary of Convertible Notes) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/ConvertibleNotesTables</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>2413404 - Disclosure - Convertible Notes (Summary of Series 2012 Notes) (Detail)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/ConvertibleNotesSummaryOfSeries2012NotesDetail</Role>
      <ShortName>Convertible Notes (Summary of Series 2012 Notes) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/ConvertibleNotesTables</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>2413406 - Disclosure - Convertible Notes (Summary of May 2015 Notes) (Detail)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/ConvertibleNotesSummaryOfMay2015NotesDetail</Role>
      <ShortName>Convertible Notes (Summary of May 2015 Notes) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/ConvertibleNotesTables</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>2413408 - Disclosure - Convertible Notes Convertible Notes (Summary of February 2018 Notes) (Detail) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/ConvertibleNotesConvertibleNotesSummaryOfFebruary2018NotesDetailDetails</Role>
      <ShortName>Convertible Notes Convertible Notes (Summary of February 2018 Notes) (Detail) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>2413410 - Disclosure - Convertible Notes Convertible Notes (Summary of December 2021 Notes) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/ConvertibleNotesConvertibleNotesSummaryOfDecember2021NotesDetails</Role>
      <ShortName>Convertible Notes Convertible Notes (Summary of December 2021 Notes) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>2413411 - Disclosure - Convertible Notes Convertible Notes (Interest Expense for December 2021 Notes) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/ConvertibleNotesConvertibleNotesInterestExpenseForDecember2021NotesDetails</Role>
      <ShortName>Convertible Notes Convertible Notes (Interest Expense for December 2021 Notes) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>2413412 - Disclosure - Convertible Notes Summary of December 2024 Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/ConvertibleNotesSummaryOfDecember2024NotesDetails</Role>
      <ShortName>Convertible Notes Summary of December 2024 Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>2413413 - Disclosure - Convertible Notes Interest Expense for December 2024 Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.pdl.com/role/ConvertibleNotesInterestExpenseForDecember2024NotesDetails</Role>
      <ShortName>Convertible Notes Interest Expense for December 2024 Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>2415402 - Disclosure - Other Long-Term Liabilities (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/OtherLongTermLiabilitiesNarrativeDetail</Role>
      <ShortName>Other Long-Term Liabilities (Narrative) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/OtherLongTermLiabilitiesTables</ParentRole>
      <Position>67</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>2415403 - Disclosure - Other Long-Term Liabilities (Other Long-Term Liabilities) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/OtherLongTermLiabilitiesOtherLongTermLiabilitiesDetail</Role>
      <ShortName>Other Long-Term Liabilities (Other Long-Term Liabilities) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/OtherLongTermLiabilitiesTables</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>2416405 - Disclosure - Stock-Based Compensation (Summary of Stock Option and Restricted Stock Award Activity) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/StockBasedCompensationSummaryOfStockOptionAndRestrictedStockAwardActivityDetail</Role>
      <ShortName>Stock-Based Compensation (Summary of Stock Option and Restricted Stock Award Activity) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/StockBasedCompensation</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>2418403 - Disclosure - Customer Concentration (Percentage of Total Revenue From Licenses Over 10% of Revenue) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/CustomerConcentrationPercentageOfTotalRevenueFromLicensesOver10OfRevenueDetail</Role>
      <ShortName>Customer Concentration (Percentage of Total Revenue From Licenses Over 10% of Revenue) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/CustomerConcentrationTables</ParentRole>
      <Position>70</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>2419402 - Disclosure - Income Taxes (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/IncomeTaxesNarrativeDetail</Role>
      <ShortName>Income Taxes (Narrative) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/IncomeTaxes</ParentRole>
      <Position>71</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>2420403 - Disclosure - Accumulated Other Comprehensive Income (Loss) (Schedule of Balances of Accumulated Other Comprehensive Income (Loss)) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/AccumulatedOtherComprehensiveIncomeLossScheduleOfBalancesOfAccumulatedOtherComprehensiveIncomeLossDetail</Role>
      <ShortName>Accumulated Other Comprehensive Income (Loss) (Schedule of Balances of Accumulated Other Comprehensive Income (Loss)) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>2422401 - Disclosure - Subsequent Events (Narrative) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/SubsequentEventsNarrativeDetail</Role>
      <ShortName>Subsequent Events (Narrative) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>2426403 - Disclosure - Intangibles and Goodwill (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/IntangiblesAndGoodwillDetails</Role>
      <ShortName>Intangibles and Goodwill (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/IntangiblesAndGoodwillTables</ParentRole>
      <Position>74</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>2426404 - Disclosure - Intangibles and Goodwill Schedule of Finite-Lived Intangible Asset Amortization Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/IntangiblesAndGoodwillScheduleOfFiniteLivedIntangibleAssetAmortizationExpenseDetails</Role>
      <ShortName>Intangibles and Goodwill Schedule of Finite-Lived Intangible Asset Amortization Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>2427402 - Disclosure - Segment Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/SegmentInformationDetails</Role>
      <ShortName>Segment Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/SegmentInformationTables</ParentRole>
      <Position>76</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>2428402 - Disclosure - Inventory (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/InventoryDetails</Role>
      <ShortName>Inventory (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/InventoryTables</ParentRole>
      <Position>77</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>2429402 - Disclosure - Stockholders' Equity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/StockholdersEquityDetails</Role>
      <ShortName>Stockholders' Equity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/StockholdersEquityNotes</ParentRole>
      <Position>78</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>2430402 - Disclosure - Revenue from Contracts with Customers (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/RevenueFromContractsWithCustomersDetails</Role>
      <ShortName>Revenue from Contracts with Customers (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/RevenueFromContractsWithCustomersTables</ParentRole>
      <Position>79</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>2430403 - Disclosure - Revenue from Contracts with Customers Contract Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/RevenueFromContractsWithCustomersContractAssetsAndLiabilitiesDetails</Role>
      <ShortName>Revenue from Contracts with Customers Contract Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>2430404 - Disclosure - Revenue from Contracts with Customers Transaction Price Allocated to the Remaining Performance Obligations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/RevenueFromContractsWithCustomersTransactionPriceAllocatedToRemainingPerformanceObligationsDetails</Role>
      <ShortName>Revenue from Contracts with Customers Transaction Price Allocated to the Remaining Performance Obligations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>81</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>2432403 - Disclosure - Leases Lease expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/LeasesLeaseExpenseDetails</Role>
      <ShortName>Leases Lease expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>2433403 - Disclosure - Investment in Evofem Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/InvestmentInEvofemNarrativeDetails</Role>
      <ShortName>Investment in Evofem Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>83</Position>
    </Report>
    <Report instance="pdli-20200331.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>2434402 - Disclosure - Assets Held for Sale (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.pdl.com/role/AssetsHeldForSaleDetails</Role>
      <ShortName>Assets Held for Sale (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.pdl.com/role/AssetsHeldForSaleNotes</ParentRole>
      <Position>84</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>pdli-20200331.xml</File>
    <File>pdli-20200331.xsd</File>
    <File>pdli-20200331_cal.xml</File>
    <File>pdli-20200331_def.xml</File>
    <File>pdli-20200331_lab.xml</File>
    <File>pdli-20200331_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/us-gaap/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
