Invest in the fundamentals and don't worry about short term swings. Celldex is poised for large-scale success and growth and those of us who have invested at these (and lower) levels will stand to gain tremendously over the next few years. The vagaries of the stock market should not concern a long-term investor.
I came into this stock as a pure speculator in June 2009. I have seen it fall all the way down to $2.05. I have bought at all levels and as recently at $13.40. I own approximately 30k shares. CLDX is one of my biggest holdings. Is there risk? Yes. But I have come to understand the science somewhat (by no means even remotely close to the knowledge possessed by Long or Frank or others who are/were in the Pharma business), I know the fundamentals and I don't care if Bernanke stops stimulus intervention or if the BOJ hikes interest rates.