Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of data-security specialist VASCO Data Security (Nasdaq: VDSI) were scorching hot today, gaining as much as 18% in intraday trading after the company reported fourth-quarter earnings.

So what: Fourth-quarter earnings per share jumped 31% from 2009, and the $0.17 reported easily topped Wall Street's $0.08 estimate. Revenue growth was a modest 3.5%, and revenue missed expectations, but cost containment -- particularly in sales & marketing and general & administrative expenses -- drove the big profit gains.

Now what: Management's guidance for 2011 was also cause for excitement; it pegged 2011 revenue growth at 20% or better, which would put the year's sales above Wall Street's current estimate. After growing like a weed for a number of years, VASCO has fallen on tougher times recently, watching its bottom line fall drastically since 2008. Could 2011 be the start of a comeback? Investors must see growth resuming, since they're currently paying a hefty 36 times expected 2011 EPS for the shares.

Want to keep up to date on VASCO? Add it to your watchlist.

VASCO Data Security International is a Motley Fool Stock Advisor pick. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.           

Fool contributor Matt Koppenheffer does not own shares of any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or on his RSS feed. The Fool’s disclosure policy prefers dividends over a sharp stick in the eye.