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 iRobot (NASDAQ:IRBT) were shorting out today, dropping as much 11% after its fourth-quarter-earnings report missed the mark.

So what: The maker of household and security-related robots said earnings per share fell from $0.54 a year ago, to $0.26, as all-around operating expenses increased significantly, though that was slightly ahead of estimates at $0.24. Revenues, however, fell 1.5%, to $124.5 million, missing estimates at $127.3 million. Though sales growth was essentially flat, CEO Colin Angle noted strong growth in the home robot business, which increased 16% over a year ago due to heavy adoption in Japan. Sales in the defense and security segment declined, in part, due to the government shutdown.

Now what: iRobot lowered the top end of its full-year revenue guidance to $490 million, from $495 million, and now expects sales of $485 million-$490 million. It also adjusted its EPS guidance from $0.88-$1.00, to $0.90-$0.95, and both projections were below analyst estimates of $492 million in revenue and $0.98 EPS. For a stock with a P/E of 38, growth seems to be coming awfully slowly. While its technology gives it a unique position in the market, the stock may a bit overvalued at this point, especially since shares had doubled from the end of the last year.

Fool contributor Jeremy Bowman has no position in any stocks mentioned. The Motley Fool recommends iRobot. 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.