I have an idea for a current software company regarding their user interface. How would I find out if my idea is worth anything without it being stolen?
~ Spokane, Wa
My clients have shown me that the best way to find out if an idea has value is to take the idea, and, commercialize it. The marketplace will tell you ultimately if it has value.
Ideas, by themselves, typically have little value. The ability to execute an idea has usually has greater value.
On the other hand, commercialization is not always possible by the person the conceives the invention. Filing a patent application allows you to protect the invention (not exactly the same as an idea). If the patent application describes a new, useful and non-obvious (these are all legal terms-of-art with special meanings), then a patent may grant that will prevent competitor from taking advantage of the invention without permission from the patent owner.
Good luck with your software idea.