Thats always the question (or the answer) on one's mind when a stock like this has taken off.  

The answer by many is to take half out when it has doubled.  Others will say take out your original investment at some point so that you are playing with the "houses" money.  Some say to sell before the news. (good or bad).  Some say, when you believe in a stock and a company, just let it ride...knowing things will only get better from here on in, perhaps going in and out with a trading position.  (I am in that camp.) 

In the end it all comes down to ones personal preference, risk tolerance and financial goals.  Whatever your decision, make sure you think about it with a sound mind beforehand.  Because once the Sell button is pushed, your decision has been made and you will forever:

1)  Be happy with your new found wealth

2)  Be miserable as you watch it continue its upward trajectory.

3)  Be upset with yourself for selling too soon

4)  Be proud of yourself because you timed it right.

Good luck to us all.

Crow  {