Bug with withinMiles in parse.com javascript geo queries api

I think I've found a bug in the pasre.com javascript Geo Queries API. I'm constructing a query like so:

var query = new Parse.Query("Location");
query.near("center", parseLocation);
query.withinMiles(15.0);
query.limit(10);
return query.find().then(function (locations) { ... });

When I execute this query I get the following error:

Failed location lookup: 102 $maxDistance needs float

And when I remove the withinMiles line it works fine. I'm basing my code on this documentation; any ideas if I'm somehow misusing the API?