Once you have defined an idea, you should protect it. However, there is a hitch – an idea cannot be patented or protected under any other kind of intellectual property rights. An idea is considered to be inside the head of an innovator. It is only after an idea is realized, in one way or another, that it may be protected.
A patent, thus, does not protect an idea, but rather a specific solution of technical nature whose realization has required intellectual work.