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.