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.

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