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 NuVasive (NASDAQ:NUVA) climbed 10% today after its preliminary results and guidance topped Wall Street expectations.

So what: NuVasive shares were slaughtered in early October on fears that lower-priced rivals were rapidly stealing market share, but today's preliminary 2012 results -- revenue of $619 million versus its prior view of $601 million-$606 million -- coupled with upbeat guidance for 2013 suggest that management's turnaround plan is working. The company cited a range of new products and geographic expansion for the bright outlook, giving investors some much-needed optimism over its growth prospects going forward.

Now what: Management now sees 2013 revenue of $655 million, nicely ahead of the consensus estimate of $638 million. "We anticipate that our market share taking strategy and momentum can be sustained in 2013," Chairman and CEO Alex Lukianov said. "The entire NuVasive family remains laser focused on changing spine surgery with innovative solutions and executing our market share taking strategy to fuel growth at several multiples of the industry while improving operating profitability."

More important, with the stock still down more than 30% from its 52-week highs, there's probably plenty of room left to buy into that bullishness.

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.