Can you hold a trademark if you hire someone else to develop your idea?

I have an idea for a piece of web software that I want designed for a site I am planning. As far as I know nothing else exists that does exactly what I want. However, I don't have the programming skills to make it myself. I suspect that if it catches on others may want to use my same idea. Can I trademark the idea behind the web software and then hire someone else develop it for me?