Could NOT find Doxygen error in ccmake

I'm on Kubuntu 14.04.3. I installed all libraries listed in the README. When I tried to configure morpheus using ccmake I got the following error:

CMake Error at /usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:108 (message):
   Could NOT find Doxygen (missing: DOXYGEN_EXECUTABLE)
 Call Stack (most recent call first):
   /usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:315 (_FPHSA_FAILURE_MESSAGE)
   /usr/share/cmake-2.8/Modules/FindDoxygen.cmake:85 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
   gui/CMakeLists.txt:38 (FIND_PACKAGE)