There's no such thing as a sure thing in the markets. I assume if you had the superpower of perfect prediction you would already be super wealthy and have no need to post on Yahoo message boards. ;) Just sayin'.
Of course no stock goes straight up - that is obvious. I was referring specifically to how the price increase since the downgap off of the conference call has come on steadily decreasing volume - that's not strong technical evidence of imminent further price upside.
Trading is not about just the potential of price action but also the probability of that price action.
(And, it's also about your compounding rate.)
Leaving gains from lower entry prices on the table until stronger evidence for a larger, more sustained up move is perfectly valid (and good) risk management.