You're right, it is a concern for many companies. However, as services like GitHub, EngineYard, and Heroku show, many companies are willing to send their code to 3rd party services if the value proposition is compelling and the security is good.
In the future, we're certainly going to work to support more languages, but we felt it was important to focus on a single language early on.
You're basically competing with LSF, which is well-supported but quite expensive. Maybe you should consider broadening to more languages?