This question point to the logic behind the practice of calling ideas a ‘brain child’. It is natural to feel protective or even shield it jealously especially if you consider it to be unique. It is also not helpful that top entrepreneurs such as Mark Zuckerberg and Steve Jobs have been accused of stealing ideas at one point or the other. Scenarios like these are what likely pressures innovators to hide their billion-dollar idea from others.
Ironically, what an innovator just starting out should do is to speak to as many people as possible about the idea. This is founded on the fact that if your idea is really unique, it will be hard to copy.

Beyond just being unique, you have to get the backing of the law. Doing this means that you register for a patent, or copyright, protecting your intellectual property from being duplicated by ‘Idea-Thieves’ as it were.