<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xml:lang="en-US"
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2021"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef xlink:href="ardx-20230302.xsd" xlink:type="simple"/>
    <context id="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001437402</identifier>
        </entity>
        <period>
            <startDate>2023-03-02</startDate>
            <endDate>2023-03-02</endDate>
        </period>
    </context>
    <dei:EntityCentralIndexKey
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV80L2ZyYWc6Yzg0OWNjMmU3OTI1NGUzYzkwMDUwODhkODg0ZjRmNzMvdGFibGU6ODA3NzllMTU2MGNiNGFkY2JlNDBkMzgzMzkxNjgxZGYvdGFibGVyYW5nZTo4MDc3OWUxNTYwY2I0YWRjYmU0MGQzODMzOTE2ODFkZl8yLTEtMS0xLTQ2MDE2_9e10fe17-1e88-4c15-9aa0-e692c1ee449d">0001437402</dei:EntityCentralIndexKey>
    <dei:AmendmentFlag
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV80L2ZyYWc6Yzg0OWNjMmU3OTI1NGUzYzkwMDUwODhkODg0ZjRmNzMvdGFibGU6ODA3NzllMTU2MGNiNGFkY2JlNDBkMzgzMzkxNjgxZGYvdGFibGVyYW5nZTo4MDc3OWUxNTYwY2I0YWRjYmU0MGQzODMzOTE2ODFkZl8zLTEtMS0xLTQ2MDE2_474c86ad-8c73-4dbf-ab91-7164566daf52">false</dei:AmendmentFlag>
    <dei:DocumentType
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGV4dHJlZ2lvbjo0OTFiYmYwZGY3OGI0NGRlOGYxMDg5NjlhZjlhMjk0OF8xMjU4_b0ad52ce-baf0-4a78-87b8-cc25fa315c6b">8-K</dei:DocumentType>
    <dei:DocumentPeriodEndDate
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGV4dHJlZ2lvbjo0OTFiYmYwZGY3OGI0NGRlOGYxMDg5NjlhZjlhMjk0OF8yMzE_093b37c8-7fa8-4ae4-ad35-ff1c4ba918d4">2023-03-02</dei:DocumentPeriodEndDate>
    <dei:EntityRegistrantName
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGV4dHJlZ2lvbjo0OTFiYmYwZGY3OGI0NGRlOGYxMDg5NjlhZjlhMjk0OF8xMjU5_524c304c-6714-47a8-acef-e4a781a27b5c">ARDELYX, INC.</dei:EntityRegistrantName>
    <dei:EntityIncorporationStateCountryCode
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGFibGU6YzU1OGQyZWIxMWY4NDA5OGI5YWJhYjkwNTQzOWVkM2QvdGFibGVyYW5nZTpjNTU4ZDJlYjExZjg0MDk4YjlhYmFiOTA1NDM5ZWQzZF8wLTAtMS0xLTQ2MDE2_5e912e2e-f879-41c4-b08f-6cd2d911c01c">DE</dei:EntityIncorporationStateCountryCode>
    <dei:EntityFileNumber
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGFibGU6YzU1OGQyZWIxMWY4NDA5OGI5YWJhYjkwNTQzOWVkM2QvdGFibGVyYW5nZTpjNTU4ZDJlYjExZjg0MDk4YjlhYmFiOTA1NDM5ZWQzZF8wLTEtMS0xLTQ2MDE2_94ce5a34-5f30-4550-86ea-f61d8ca8010d">001-36485</dei:EntityFileNumber>
    <dei:EntityTaxIdentificationNumber
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGFibGU6YzU1OGQyZWIxMWY4NDA5OGI5YWJhYjkwNTQzOWVkM2QvdGFibGVyYW5nZTpjNTU4ZDJlYjExZjg0MDk4YjlhYmFiOTA1NDM5ZWQzZF8wLTItMS0xLTQ2MDE2_c9d61d90-50fc-441b-86fd-4ecc114e8a9b">26-1303944</dei:EntityTaxIdentificationNumber>
    <dei:EntityAddressAddressLine1
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGV4dHJlZ2lvbjo0OTFiYmYwZGY3OGI0NGRlOGYxMDg5NjlhZjlhMjk0OF8xMjU1_9bb08b47-290c-4532-9152-5794575f0ae7">400 FIFTH AVE.</dei:EntityAddressAddressLine1>
    <dei:EntityAddressAddressLine2
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGV4dHJlZ2lvbjo0OTFiYmYwZGY3OGI0NGRlOGYxMDg5NjlhZjlhMjk0OF8xMjY0_adc8e764-990e-4b7b-9629-bd5941a2f4c4">SUITE 210</dei:EntityAddressAddressLine2>
    <dei:EntityAddressCityOrTown
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGV4dHJlZ2lvbjo0OTFiYmYwZGY3OGI0NGRlOGYxMDg5NjlhZjlhMjk0OF8xMjU2_5c6bf862-5660-4a4a-ae8a-625997d94f9b">WALTHAM</dei:EntityAddressCityOrTown>
    <dei:EntityAddressStateOrProvince
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGV4dHJlZ2lvbjo0OTFiYmYwZGY3OGI0NGRlOGYxMDg5NjlhZjlhMjk0OF8xMjYw_415e29ea-f487-4723-9470-3356101365af">MA</dei:EntityAddressStateOrProvince>
    <dei:EntityAddressPostalZipCode
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGV4dHJlZ2lvbjo0OTFiYmYwZGY3OGI0NGRlOGYxMDg5NjlhZjlhMjk0OF8xMjYx_a8c01f1d-e1cc-4f9a-8881-d0a745427857">02451</dei:EntityAddressPostalZipCode>
    <dei:CityAreaCode
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGV4dHJlZ2lvbjo0OTFiYmYwZGY3OGI0NGRlOGYxMDg5NjlhZjlhMjk0OF8xMjU3_9e81e431-8f6c-4fee-9b49-1902bc8604b5">510</dei:CityAreaCode>
    <dei:LocalPhoneNumber
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGV4dHJlZ2lvbjo0OTFiYmYwZGY3OGI0NGRlOGYxMDg5NjlhZjlhMjk0OF8xMjYy_6c875597-f91d-4ae9-be4b-d07083ec0032">745-1700</dei:LocalPhoneNumber>
    <dei:WrittenCommunications
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGFibGU6MGQ5OTY5YjJmNTk2NDdhYzk0MzRkM2I4ZDIzNjJiZjUvdGFibGVyYW5nZTowZDk5NjliMmY1OTY0N2FjOTQzNGQzYjhkMjM2MmJmNV8wLTAtMS0xLTQ2MDE2_aae6df74-68f7-4966-8461-a61c93e5cdb8">false</dei:WrittenCommunications>
    <dei:SolicitingMaterial
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGFibGU6MGQ5OTY5YjJmNTk2NDdhYzk0MzRkM2I4ZDIzNjJiZjUvdGFibGVyYW5nZTowZDk5NjliMmY1OTY0N2FjOTQzNGQzYjhkMjM2MmJmNV8xLTAtMS0xLTQ2MDE2_090cbf4e-c64f-4ca1-91fc-e3ae3e36e013">false</dei:SolicitingMaterial>
    <dei:PreCommencementTenderOffer
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGFibGU6MGQ5OTY5YjJmNTk2NDdhYzk0MzRkM2I4ZDIzNjJiZjUvdGFibGVyYW5nZTowZDk5NjliMmY1OTY0N2FjOTQzNGQzYjhkMjM2MmJmNV8yLTAtMS0xLTQ2MDE2_5257f27b-827c-4c34-bca3-aa31b8301aa2">false</dei:PreCommencementTenderOffer>
    <dei:PreCommencementIssuerTenderOffer
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGFibGU6MGQ5OTY5YjJmNTk2NDdhYzk0MzRkM2I4ZDIzNjJiZjUvdGFibGVyYW5nZTowZDk5NjliMmY1OTY0N2FjOTQzNGQzYjhkMjM2MmJmNV8zLTAtMS0xLTQ2MDE2_a9eb5a8a-a1f7-42af-8fc8-2d7756d5c182">false</dei:PreCommencementIssuerTenderOffer>
    <dei:Security12bTitle
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGFibGU6ODZlMjA2MmE3N2U1NDQ0OWIwY2M2MDY3ZjAyNzM4ZWEvdGFibGVyYW5nZTo4NmUyMDYyYTc3ZTU0NDQ5YjBjYzYwNjdmMDI3MzhlYV8xLTAtMS0xLTQ2MDE2_c3a16731-6c3d-4986-a65f-cde31da60575">Common Stock, par value $0.0001</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGFibGU6ODZlMjA2MmE3N2U1NDQ0OWIwY2M2MDY3ZjAyNzM4ZWEvdGFibGVyYW5nZTo4NmUyMDYyYTc3ZTU0NDQ5YjBjYzYwNjdmMDI3MzhlYV8xLTItMS0xLTQ2MDE2_65ccdb1b-141b-4ec9-a83d-9a24f774485b">ARDX</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGFibGU6ODZlMjA2MmE3N2U1NDQ0OWIwY2M2MDY3ZjAyNzM4ZWEvdGFibGVyYW5nZTo4NmUyMDYyYTc3ZTU0NDQ5YjBjYzYwNjdmMDI3MzhlYV8xLTQtMS0xLTQ2MDE2_174bbde9-38fb-4408-9205-df3c79523750">NASDAQ</dei:SecurityExchangeName>
    <dei:EntityEmergingGrowthCompany
      contextRef="ia3692c3ea86540e69020b7ac30670151_D20230302-20230302"
      id="id3VybDovL2RvY3MudjEvZG9jOjI1ODY4YjEzYmIwNTQ0ZTBiNmVlN2U0N2Y3ZDA1NTQ5L3NlYzoyNTg2OGIxM2JiMDU0NGUwYjZlZTdlNDdmN2QwNTU0OV8xL2ZyYWc6NDkxYmJmMGRmNzhiNDRkZThmMTA4OTY5YWY5YTI5NDgvdGV4dHJlZ2lvbjo0OTFiYmYwZGY3OGI0NGRlOGYxMDg5NjlhZjlhMjk0OF8xMjYz_5e152cd7-d6d5-4510-80b1-6e57d2b78967">false</dei:EntityEmergingGrowthCompany>
</xbrl>
