Tesla - high flying stock.

Telsa (TSLA) has posted gains of over 400% year to date. It's a stock that I've been looking at but I feel I missed the boat on this. Stock prices have skyrocketed with only expectations that it will do well and get into a new market that no one has entered before. They have exceeded expectations in their earnings but who knows how sustainable this stock is. I've been wonder if it will come back to earth any time soon. I'm staying on the sidelines for this. Any one else have any comments?