<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:01a000f4-5b5e-72f0-b795-294fe6786e02,g:d4594dcf-5f4b-40a5-bdf6-b64da2b892bb-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#IndividualsOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllIndividualsMember" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#ecd_AllIndividualsMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_csbr_Dr.MorrisMember_01a03541-85b9-7383-8419-8986f7a525a8" xlink:href="csbr-20260828.xsd#csbr_Dr.MorrisMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_csbr_Dr.MorrisMember_01a03541-85b9-7383-8419-8986f7a525a8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_csbr_Mr.BraininMember_01a03551-f691-7f31-9c38-1e469f4e7767" xlink:href="csbr-20260828.xsd#csbr_Mr.BraininMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_csbr_Mr.BraininMember_01a03551-f691-7f31-9c38-1e469f4e7767" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_csbr_RonnieMorrisMember_01a03540-e727-7227-b916-551abefccccf" xlink:href="csbr-20260828.xsd#csbr_RonnieMorrisMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_csbr_RonnieMorrisMember_01a03540-e727-7227-b916-551abefccccf" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/PvpAdjustmentsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#PvpAdjustmentsOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/PvpAdjustmentsOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllAdjToCompMember" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#ecd_AllAdjToCompMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_csbr_IncrementalFairValueOfOptionsSARsModifiedDuringTheApplicableFiscalYearMember_01a000f4-5b5e-736a-8680-38162f0526ef" xlink:href="csbr-20260828.xsd#csbr_IncrementalFairValueOfOptionsSARsModifiedDuringTheApplicableFiscalYearMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllAdjToCompMember" xlink:to="loc_csbr_IncrementalFairValueOfOptionsSARsModifiedDuringTheApplicableFiscalYearMember_01a000f4-5b5e-736a-8680-38162f0526ef" xlink:type="arc" order="4"/>
  </link:definitionLink>
</link:linkbase>
