You can't stop it getting out. So two solutions - stop people wanting to hurt you, and have legal precautions. To stop people hating you treat them right (saying more is probably off topic for stack overflow).
I'm not a lawyer, but to give yourself legal protection, if you believe in it, patent the ideas, put a copyright notice in the code, and make sure the contracts for your programmers specify carefully intellectual property rights.
But at the end of the day, the answer is run quicker than the competition.