If you are not a tech guy, it is highly recommended to find a local good and enthusiastic Project Manager/CTO. It would be a good idea to further sparkle his enthusiasm by offering him some equity ownership. At the same time, your project is your baby. So you will never sit aside, but will regularly give recommendations or new directives.
As for development team, I’d chose an offshore company with years of experience and lots of clients to ask for recommendations. (Why? After working as a Business Development Manager at an Offshore Software Development Company for many years, I have a strong opinion that offshore teams work not worse, but often even harder and with more dedication than local teams. Besides, this is cheaper.)
Be sure to ask the company for experience in similar projects and for client references, for whom they have developed projects on technologies selected by you. Pick up those with a long cooperation history, as well as new clients - the fresher, the better.
Ask the company to give estimation of your project, having provided them with specification and all available information. Try to evaluate proficiency of their work already at this stage (quality of specifying questions, promptness of response, readability of their offer, transparency of their estimation).
When you set up your mind on proceeding with a certain company, get acquainted with the development team, but first and foremost with the Project Manager / Team Lead, to understand his proficiency level and dedication. You should be comfortable in communicating with him. And he should be easy to reach.
If you could start with a small test project, this would be good, so you could check manner of work and results.
Weekly reporting is a must.
Clear documentation and readability of code is also required. Who knows, perhaps, one day you decide to change a team. Or upon development completion you will hire a person to support the project, which is very likely.
BTW, everything mentioned above is also valid if you decide to hire a local development team.
But if you lean to a team overseas, drop me a line at FD, and I will connect you with a few trusted IT companies, whom I can only recommend!