What about Atom (atom.io) as an IDE?
Your mileage may vary, but personally I’ve found that Atom works great as an IDE for a multitude of languages, including Lua as I recently discovered. It’s also quite easy to get it set up to work properly with Defold. The package for Lua support (language-lua) recognizes the .lua extension, so for any scripts you open you need to specify them as Lua files with the shortcut control-shift-L (same shortcut on OS X, not command but control).