You need to clearly declare a prior art detailing your idea to protect it in the first place. This can be done by writing down your idea and having three people

You need to clearly declare a prior art detailing your idea to protect it in the first place. This can be done by writing down your idea and having three people attest and sign on it. Another method is to file your idea with an organization such as Writers guild of America http://www.wga.org http://www.wga.org. But to make commercial use of your idea, you need to file a patent in every country you plan to do business.