Lyndon Rive, the co-founder and former CEO of SolarCity, did not attend last week's call with reporters when Tesla unveiled new details about the Solar Roof. It was a sign of a coming change. Today, Rive announced that he will be leaving Tesla to focus on building a new company. "I am an entrepreneur at heart; starting and growing companies is what I do best. I want to pursue a new venture, but I didn't want to do that until the time was right.