ACHN - Not necessarily. I don't hold ACHN (unfortunately) but I think another reason for releasing data early may have been to sign a partnership early. Within the next few days if there is no dilution at these prices I would bet that some deal would be announced. At close to $4 ACHN will have a marketcap of a little more than 100 million. As a comparison ANDS is slightly below 100 million.
I dont feel bad for the people who buy on this news - if you are chasing momentum then by definition you're a sheep - and sheep get sheared. We all need sheep to make money - just don't be the sheep.
Now remember the RULE - ALWAYS SELL INTO THE volume days when they are way above normal - tops are set that day or the next nearly 100% of the time. The next few weeks they give back the big gains as it digests the volume and churns lower as the volume declines. Mushroom cloud effect.