Your IP has probably already been stolen if you filed a patent at the patent office outside Washington. Have you ever been to the office? It's like going to a UN convention. Further, I believe there are different confidentiality rules for US versus foreign patents, but you would have to check with your lawyer. Practically, for most small companies, patents are just about worthless. Many new entrepreneurs misunderstand the value patents create, and how difficult they are to enforce. A patent is for offensive purposes, not defensive. It gives you the right to sue a party who makes commercial use aka infringes on your patent. It does not give you the right to practice your technology free of interference. There are actually organizations that exist solely to sue you or threaten litigation for infringement like "greenmail" i.e. the practice of spending enough money to threaten you and/or litigate to force the small IP owners to sell or even give them the IP, which is economically better than litigating. The bad news is the better your invention and more valuable the prospects the greater the chance that others will copy or come after you. You generally can trust every other party to do what is in their best interests - not yours. This is not a pessimistic view. Pessimists are, in my view, simply profound optimists who know too much. All you can do is charge ahead - fast. This is a risk that is generally uncontrollable. Good luck.
We have a company that sources electronics and other complex products for U.S. manufacturers in China. In our 30 years’ experience we have had a few problems, but for the most part find things are OK. Having said that, though, I would still take the proper precautions including:
Patent protection if possible.
Copyright of designs and trade dress.
Formal Non-Disclosure agreements.
Careful screening and vetting of vendors.
Candid discussions with company management.
QC inspectors working for you who are in the factory after every production run with their eyes wide open to possible violations.
If, up front, vendors know you are serious about protecting your intellectual property they are far less likely to play games.