diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7a688cf..3eb2317 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -38,25 +38,18 @@ endif(VMA_BUILD_SAMPLE)
 option(BUILD_DOCUMENTATION "Create and install the HTML based API documentation (requires Doxygen)" OFF)
 
 if(BUILD_DOCUMENTATION)
-    if(PROJECT_IS_TOP_LEVEL)
-        find_package(Doxygen)
-    endif()
-    if(DOXYGEN_FOUND)
-        # set input and output files
-        set(DOXYGEN_IN ${CMAKE_CURRENT_SOURCE_DIR}/Doxyfile)
-        set(DOXYGEN_OUT ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile)
-
-        # request to configure the file
-        configure_file(${DOXYGEN_IN} ${DOXYGEN_OUT} @ONLY)
-        # note the option ALL which allows to build the docs together with the application
-        add_custom_target( doc_doxygen ALL
-            COMMAND ${DOXYGEN_EXECUTABLE} ${DOXYGEN_OUT}
-            WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
-            COMMENT "Generating API documentation with Doxygen"
-            VERBATIM )
-    else()
-        message("Doxygen need to be installed to generate the doxygen documentation")
-    endif()
+    find_package(Doxygen REQUIRED)
+    # set input and output files
+    set(DOXYGEN_IN ${CMAKE_CURRENT_SOURCE_DIR}/Doxyfile)
+    set(DOXYGEN_OUT ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile)
+    # request to configure the file
+    configure_file(${DOXYGEN_IN} ${DOXYGEN_OUT} @ONLY)
+    # note the option ALL which allows to build the docs together with the application
+    add_custom_target( doc_doxygen ALL
+        COMMAND ${DOXYGEN_EXECUTABLE} ${DOXYGEN_OUT}
+        WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+        COMMENT "Generating API documentation with Doxygen"
+        VERBATIM )
 endif()
 
 add_subdirectory(src)