This image released by CBS shows, from left, Simon Helberg, Melissa Rauch, Mayim Bialik and Jim Parsons in a scene from "The Big Bang Theory."
This image released by CBS shows, from left, Simon Helberg, Melissa Rauch, Mayim Bialik and Jim Parsons in a scene from "The Big Bang Theory." CBS says it's renewing its hit comedy "The Big Bang Theory" for three more years. (Michael Yarish/AP Photo/CBS)