Just as a general rule, I tell myself not to chase a stock price... and that goes double when the price is up 20+%. I have been guilty of letting my emotion get the better of me and doing it on multiple occasions, and every time, I have regretted it when it put me in the red.
You always have to do what you feel is right, but just remember that sustained growth over 20% with no pull back and no news, isn't common.