I'm going to take a guess and say that it's not CGI at all, just tracked very precisely and cropped. Since the rolling die will always have a shape of a circle, you need to track just the circle. Also you can see the background change somewhat as it travels across the surface (this could be of course simulated too). In theory, you would place a top-down camera above a desk, record the entire desk, roll the die, then track it and crop it.

If it is CGI, it's very good.