Currently your idea is as good as mine. Funimation licensed the 1st season and the 2nd season. It's possible a 3rd season will be obtained by Funimation in the future, but I have my own thoughts for this. It has been rumored that a 3rd season has been in the works. Many had speculated we would get a announcement for it for the new 2017 Winter Season though that didn't happen. At this point unless their actual website or big name news outlet announces a release for a 3rd season I wouldn't believe other sources. Now going back to my thoughts I would anticipate a late 2017 release for a 3rd season or possible early 2018. For now the best thing you can do is follow BONES studio as they'll likely announce any news pertaining to Noragami since having worked on the project. Well I hope this helps answer your question, but for now we really just have to wait.