Are you saying that the options makers don't see ARIA moving in either direction (a large % movement)...up or down?
That's interesting.
As I said earlier in the week, when I start to see the options markers pick up in this stock, and start trading in large blocks in several of the expirations....then it's time to get nervous.
First there is a big difference between an option with a 30% vs 50% premium. Second if that is your only example I don't think you have a supportable position. Also look at the implied volatility of Ariad's options They have always been relatively high.