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 Procera Networks (NASDAQ:PKT) dropped today by as much as 30% after the company reported worse-than-expected earnings.

So what: Revenue in the fourth quarter added up to $16.6 million, which didn't compare well to the $19.1 million consensus estimate. Non-GAAP net income totaled $2.4 million, or $0.12 per share, also shy of the $0.14 per share profit that investors were hoping for. The company said it generated record bookings of $22.4 million.

Now what: Guidance for 2013 calls for growth to increase by 25% to 30%, as the company expects to gain market share this year. Procera may post operating losses in the first half of the year, but should rebound during the second half. Two firms are defending the stock, Raymond James and William Blair. William Blair analyst Jason Ader thinks the sell-off is excessive while sticking with his outperform rating.

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Fool contributor Evan Niu, CFA, has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. 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. The Motley Fool has a disclosure policy.