Imo, it is 100% caused by opportunistic hedge funds and retail shorts just running down a little biotech company that has a history of this sort of thing.
Sorry boys but I believe you are not seeing the forest through the trees here. Rida is a nice sidebar for Aria but the real value of this company lies in Pona. Ariad is on sale right now.
I can make same argument that you see too much forest without looking at each tree. If rida were just a nice sidebar as you claimed, wouldn't ARIA stock price go back to where it was before it jumped after rida data in sarcoma in Jan2011?
I and many others don't think a company like ARIA with $750m market cap is on sale.