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 FireEye (NASDAQ:FEYE) plunged 11% Wednesday after the cyber-security specialist beat expectations with its fourth-quarter results, but followed with disappointing forward guidance.

So what: Quarterly revenue rose 81% year over year to $57.3 million, which translated to an adjusted net loss of $40.5 million, or $0.35 per share. Analysts were looking for a wider loss of $0.38 per share on sales of $56.06 million.

However, FireEye expects first quarter revenue in the range of $70 million to $72 million on billings of $84 to $88 million, which should result in a loss per share of $0.51 to $0.56. By contrast, analysts were modeling a loss of just $0.37 per share on sales of $76.16 million.

In addition, FireEye stated full-year 2014 sales should be in the range of $400 million to $410 million, with a loss per share of $2.00 to $2.20. The midpoint of both ranges stands below analysts' expectations for a loss of $1.42 per share on sales of $406.52 million. 

Now what: Those losses can be attributed to large chunks of cash allocated to both R&D and sales and marketing -- as a percentage of sales, FireEye says the two categories will cost around 36% to 39% and 82% to 85% of revenue in 2014, respectively.

To be sure, with the stock trading at a lofty 59 times last year's sales, FireEye needs to continue accelerating its top-line to eventually achieve sustained profitability. And it definitely needs to invest in R&D to stay on top of the latest cyber threats it aims to negate.

As it stands, however, I'd personally prefer to wait at least another quarter to see whether some of that significant top-line growth will come to fruition. If FireEye can deliver then, I might just be convinced it has what it takes to grow into its nearly $10 billion market cap.