Seems like a great way to validate your idea on someone else's dime. If it works out you can consider what your options are at that point, including leaving and

Seems like a great way to validate your idea on someone else's dime. If it works out you can consider what your options are at that point, including leaving and setting up a competing company. If it doesn't, you can analyze why and either make the case for trying again at your company, on your own or decide to let it go altogether. I don't really see any downside at this point.