diff --git a/doc/CMakeLists.txt b/doc/CMakeLists.txt
--- a/doc/CMakeLists.txt
+++ b/doc/CMakeLists.txt
@@ -17,6 +17,15 @@
   @ONLY
 )
 
+# Copy doc from source (if exists)
+IF(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/html AND 
+    NOT EXISTS ${CMAKE_CURRENT_BINARY_DIR}/html/index.html)
+  MESSAGE(STATUS "Copy doc from source tree")
+  EXECUTE_PROCESS(
+    COMMAND cmake -E copy_directory ${CMAKE_CURRENT_SOURCE_DIR}/html ${CMAKE_CURRENT_BINARY_DIR}/html
+    )
+ENDIF()
+
 IF(DOXYGEN_EXECUTABLE AND PYTHONINTERP_FOUND AND GHOSTSCRIPT_EXECUTABLE)
   FILE(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/html/)
   SET(GHOSTSCRIPT_OPTIONS -dNOPAUSE -dBATCH -q -dEPSCrop -dTextAlphaBits=4 -dGraphicsAlphaBits=4 -sDEVICE=pngalpha)