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) plunged nearly 20% Tuesday, after the company announced disappointing preliminary fourth-quarter and full-year 2013 revenue results.

So what: Procera still isn't expected to announce earnings until sometime next month but stated that fourth-quarter revenue is now expected to be in the range of $20.9 million to $21.4 million, an increase of 26% to 29% over the same year-ago period. As a result, fiscal 2013 revenue should be in the range of $74.1 million to $74.6 million, an increase of 24% to 25% over fiscal 2012.

And that would have been well and good -- at least until we remember Procera's guidance in November called for annual revenue growth of at least 30%.

Now what: Procera President and CEO James Brear weighed in, saying the subpar performance is largely owed to "reduced orders from the U.S. Cable market," which is facing "uncertainty and potential consolidation." Nonetheless, he insisted, "While we are disappointed by our total revenue performance, our growth drivers are intact and our competitive position remains strong."

Even so, with the stock currently trading at a lofty 27 times next year's estimated earnings -- and keeping in mind those estimates are likely to fall given today's revenue weakness -- I'd prefer to wait for more details on the miss during the company's earnings conference call before making any decisions regarding Procera stock.

Fool contributor Steve Symington and The Motley Fool have no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools don't 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.