What is the best strategy to prevent someone from stealing our technology pre-patent?

I have to respectfully take issue with one point that Jing made - while your patent application is pending, you do NOT necessarily have the right to commercialize it, and even after you obtain your patent, you do not necessarily have the right to commercialize is because a patent does not give any rights to make, sell, or use your own patented invention - a patent gives you the right to prevent OTHERS from making using, or selling your patented invention, so whether your application is pending, or even after your patent has issued, you have to be careful that manufacturing or selling your patented invention does not infringe someone else's patent. Also, note further that when your patent application is published, it effectively puts the world on notice that you may obtain a patent in the near future for the claimed invention, and therefore, if there are infringers, they will likely be held liable for severe penalties because they were already aware of your potential patent and chose to proceed to effectively infringe anyway.