Using sphinx-api-doc when both sphinx and django are in multiple virtualenv
The api documentation for your code can only be generated with proper access to your code, so the anser will be "no, you'll need to have them both in the same virtualenv".
Some extra thoughts:

If your code virtualenv isn't isolated from the system's python packages, you could install sphinx globally, but you probably don't and shouldn't want that.
I'd just add sphinx to your code's virtualenv. I don't think you'll have to worry about extra overhead of a few extra kilobytes.
I have multiple django projects running different django versions in their own virtualenv. I want to use sphinx-api-doc command to generate api docs for the django projects. However i dont want to install sphinx directly in the system and would like to install it in a separate virtualenv.
Since only one virtualenv can be activated at a time, i am not able to use sphinx-api-doc. Is there a way to use sphinx-api-doc with sphinx and django in independent virtualenv or is installing sphinx directly in the system the only way to go?