You are correct. There seems to be plenty of people willing to sell, but don't think some of the funds aren't playing both sides of this as well. They can and do make money both ways. Seen it way too many times with this particular stock.
Cab, you are wrong. There are no significant numbers of shares available. You are not seeing investors selling, you are seeing manipulators and shorts trading the same shares back and forth to each other. They do it on days when there is a lack of strong buying, such as one where the biotech sector is weak. Today is a perfect example. All traders, not investors.