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 Cognex Corporation (NASDAQ:CGNX) fell more than 16% during Friday's intraday trading, then recovered to close down around 8% after the company released solid fourth-quarter results, but followed with disappointing forward guidance.

So what: Quarterly sales rose 16% year over year to $95.7 million, which translated to 21% growth in net income per share, to $0.23. Analysts, on average, were only expecting earnings of $0.22 per share on sales of $94.67 million.

However, Cognex anticipates current quarter revenue between $88 million and $91 million, the midpoint of which sits well below expectations for Q1 sales of $91.43 million.

Now what: The top-line guidance miss wasn't that bad, which explains why the stock partially recovered into the close. However, Cognex certainly doesn't look cheap -- even after today's fall -- trading around nine times last year's sales, and 29 times this year's expected earnings. For now, even though Cognex certainly isn't a broken company, I still prefer waiting on the sidelines for a more attractive entry point going forward.

Steve Symington has no position in any stocks mentioned. The Motley Fool recommends Cognex. 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.