Collegium Pharmaceutical (COLL) shares rallied 10.6% in the last trading session to close at $38.60. This move can be attributable to notable volume with a higher number of shares being traded than in a typical session. This compares to the stock's 7% gain over the past four weeks.Earlier this week, the company announced a definitive agreement to acquire a privately held, pharmaceutical company, Ironshore, for $525 million in cash with the potential for an additional $25 million commercial milestone payment ...