When Sphinx has been configured to use the readthedocs (i.e., sphinx_rtd_theme), the sphinxserve project doesn't work properly, because as far as I can tell jquery isn't included up until a later stage in the document, and as such the $-sign hasn't been defined yet.
A temporary workaround is using the default theme & it looks like a more proper workaround would be placing the injected javascript at the very end of the document.