diff --git a/doc/CMakeLists.txt b/doc/CMakeLists.txt
index 56825a23..7b531f65 100644
--- a/doc/CMakeLists.txt
+++ b/doc/CMakeLists.txt
@@ -1,7 +1,4 @@
-add_custom_command(OUTPUT html/index.html
+add_custom_target(doc
   COMMAND doxygen
   COMMAND rm -rf html
-  COMMAND sphinx-build -b html . html
-  DEPENDS ../CMakeLists.txt ../format.h Doxyfile
-          conf.py index.rst _templates/layout.html)
-add_custom_target(doc DEPENDS html/index.html)
+  COMMAND sphinx-build -b html . html)