Which software license can I use that requires permission/licensing to use?

I have created some software that I intend to use within the company that I work for. Right now, it is running on a server that I own, but I am allowing free use of it within the organization, from my website. Right now, the code is private, available only to me. I would like to be able to open it up publicly for auditing and to allow others to potentially contribute. However, I want to prevent the organization that I work for from simply taking the code and using it themselves. I would like a license for my code that requires anybody that uses my code (outside of using my website/platform) to pay for it or recieve permission. Which licenses might fit this bill?