Tesla Motors (NASDAQ:TSLA) stock is down since reporting earnings, but fundamentally nothing has changed about the company. In fact, it's investors who got ahead of themselves in valuing this stock. 

The true challenges for Tesla come in the next few years as other automakers introduce increasingly competitive vehicles. Ford (NYSE:F) is betting that its Focus Electric can give it a foothold in the market and Nissan and GM have eyes on the electric vehicle space as well. But the biggest competition may be coming from Germany, where BMW's i8 is being developed with specs that can match the performance of the Model S in many ways. If BMW can get it right, then Tesla's monopoly on high-performance EVs will be over. 

Erin Miller sat down with Motley Fool contributor Travis Hoium to hear just what investors should be watching for in the future.