diff --git a/docs/Makefile b/docs/Makefile
index d0c3cbf..c3f7718 100755
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -17,4 +17,4 @@ help:
 # Catch-all target: route all unknown targets to Sphinx using the new
 # "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
 %: Makefile
-	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+	@$(SPHINXBUILD) -b $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)