What is the appropriate follow up after an interview? Hopefully you asked at the interview what the anticipated timeline and process will be for making a final decision. This will give you some idea of what you can expect.
Beyond that, after two weeks is a good time to email and possibly call to check on the status of the decision making process. They may have run into unexpected delays that you would want to know about. Remember, if they are excited to hire you, they will contact you as soon as possible to make sure no one else hires you!