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 medical device company Tornier (NASDAQ:TRNX) plummeted 24% today after its quarterly results and outlook disappointed Wall Street.

So what: The stock has rallied nicely in recent months on optimism over accelerating growth, but a third-quarter miss -- loss of $0.18 in EPS was $0.03 worse than analysts expected -- coupled with downbeat guidance is forcing Mr. Market to quickly sober up. While Tornier's revenue increased 15% over the year-ago period, adjusted EBITDA margin slipped 110 basis points to 7.2%, suggesting that its competitive position is weakening.

Now what: Management now sees full-year revenue of $299.2 million-$303.2 million, well below Wall Street's forecast of $317.38 million.

"We believe we have the infrastructure in place to support our double-digit constant currency revenue growth and enhanced operating leverage expectations," CEO Dave Mowry reassured investors.

However, with Tornier shares still sporting a particularly lofty 40-plus price-to-cash flow multiple, I'd wait for an even wider margin of safety before buying into that optimism. 

Fool contributor Brian Pacampara 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.