<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2025"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef xlink:href="ck0001726445-20260427.xsd" xlink:type="simple"/>
    <context id="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001726445</identifier>
        </entity>
        <period>
            <startDate>2026-04-27</startDate>
            <endDate>2026-04-27</endDate>
        </period>
    </context>
    <dei:EntityCentralIndexKey
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_2aeccde5-9242-4ff5-bbcd-12580c24883b">0001726445</dei:EntityCentralIndexKey>
    <dei:AmendmentFlag
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_67200edf-9afb-4795-b644-df73e4559011">false</dei:AmendmentFlag>
    <dei:DocumentType
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_b45e1b43-94f8-4433-a720-57d2bc85dda1">8-K</dei:DocumentType>
    <dei:DocumentPeriodEndDate
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_e11ab470-b594-4435-942d-41f5ca3df36d">2026-04-27</dei:DocumentPeriodEndDate>
    <dei:EntityRegistrantName
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_c9efdf8c-0c2b-4d7f-b072-63115b020f10">Seer, Inc.</dei:EntityRegistrantName>
    <dei:EntityIncorporationStateCountryCode
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_a27f6dc7-945f-4c49-8deb-766fdc8c0c16">DE</dei:EntityIncorporationStateCountryCode>
    <dei:EntityFileNumber
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_8a05a100-0486-4eff-ad24-328e47ee81ce">001-39747</dei:EntityFileNumber>
    <dei:EntityTaxIdentificationNumber
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_cec63ee6-bace-4d4b-bc04-735a778b8a68">82-1153150</dei:EntityTaxIdentificationNumber>
    <dei:EntityAddressAddressLine1
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_b010db5e-684a-406c-8765-dd93dfc37714">3800 Bridge Parkway</dei:EntityAddressAddressLine1>
    <dei:EntityAddressAddressLine2
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_0411452a-7ca2-4947-946e-5ed7e58cf65f">Suite 102</dei:EntityAddressAddressLine2>
    <dei:EntityAddressCityOrTown
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_7cfe0c69-6196-46cb-ba7a-8e4b9a4ef84b">Redwood City</dei:EntityAddressCityOrTown>
    <dei:EntityAddressStateOrProvince
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_3ac9d3e2-f98d-4627-b6c2-32b30c49bd7b">CA</dei:EntityAddressStateOrProvince>
    <dei:EntityAddressPostalZipCode
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_3b6fecf2-aa40-48e7-aefd-c331c970c5ef">94065</dei:EntityAddressPostalZipCode>
    <dei:CityAreaCode
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_622d909d-4538-41c4-9a6e-f56c1a236054">650</dei:CityAreaCode>
    <dei:LocalPhoneNumber
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_46632e69-f842-4c53-a929-6114a2a71936">453-0000 </dei:LocalPhoneNumber>
    <dei:WrittenCommunications
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_de00c4e6-83c8-47e6-a088-952508bc99d8">false</dei:WrittenCommunications>
    <dei:SolicitingMaterial
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_52c61fa8-b1d9-474d-86b4-e70f58933972">true</dei:SolicitingMaterial>
    <dei:PreCommencementTenderOffer
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_dfadbbea-56eb-4ba4-9994-5e5b2896c74f">false</dei:PreCommencementTenderOffer>
    <dei:PreCommencementIssuerTenderOffer
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_7e5387ab-16c6-453a-9b37-def2d5d0b92f">false</dei:PreCommencementIssuerTenderOffer>
    <dei:Security12bTitle
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_828a5067-bc53-4fc8-a78a-9d27efb6dd4a">Class A Common Stock, par value $0.00001 per share</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_5f37a0c9-885a-4ad5-af46-46326c46dd15">SEER</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_3a8ea8b0-1e9a-4117-8439-07b39e611b87">NASDAQ</dei:SecurityExchangeName>
    <dei:EntityEmergingGrowthCompany
      contextRef="C_9a1c2c22-52b7-40b5-92b8-66e9848fd8cb"
      id="F_eba4ae92-0218-4306-bdcc-5d055f25642b">false</dei:EntityEmergingGrowthCompany>
</xbrl>
