Allergan (NYSE: AGN) has signed its first major acquisition deal of 2017. The drugmaker inked a definitive agreement to purchase ZELTIQ Aesthetics (NASDAQ: ZLTQ) for $56.50 per share, or nearly $2.5 billion. ZELTIQ sells the CoolSculpting system, a “body contouring” method that freezes fat cells in order to speed their destruction.