I am probably out in left field here but (remember CPXX lately) many times after great trial results,the SP goes crazy.No deals inked,just great trial data.I think Mr.Market just takes the size of the market and projects market share to arrive at a reasonable SP.If a deal is done and #'s are less than expected,then the SP will follow just as with a deal that is better than expected.
That is my theory but then throw in the variables,shorts,traders,etc.then the SP will be volatile for a while as the SP settles on reality in terms of the actual value.

Just my guess,open to suggestions.

Kelt