Exelixis (EXEL) shares have surged another 11% in trading today and are now up more than 141% in the last three months. The latest rally has been sparked by strong Q2 results. Revenue for the quarter rose to $36.3 million. Given the excellent run in EXEL over the last three months, I believe it is time now to take some profit. However, I would not recommend exiting entire position as there is further upside in EXEL.