Between 4 years ago and now, this was a fantastic investment. Obviously with any of these stocks you have to trade out profits, but if you feel good about the long term of the company, you stay long.
And take a look at the last 4 years of financials. It's a bargain to buy the stock back down at this price with the change in the last few years. From consistent net losses to some relatively consistent profit. To buy a company at the same price when it is profitable compared to when it had never turned a profit? Seems like a good deal.
Everyone bailed out of SYEV after a couple low sales quarters last year.