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 specialist Boston Scientific (NYSE:BSX) climbed 12% today after its quarterly results and guidance topped Wall Street expectations. 

So what: Boston Scientific has been bruised in recent years on weak demand and market share losses, but today's second-quarter results -- adjusted EPS of $0.18 versus the consensus of $0.15 -- coupled with upbeat guidance for the full year reinforces optimism over a sustained turnaround. While sales of stents and defibrillators -- its two largest segments -- slipped yet again, the decline was much slower than in previous quarters, suggesting that top-line growth might be right around the corner.  

Now what: Management now expects 2013 EPS of $0.67 to $0.71, up from its prior view of $0.65 to $0.70, and revenue of $7.05 billion to $7.17 billion. "We are pleased with our improved performance during the quarter," said President and CEO Mike Mahoney. "As we continue to expand our portfolio, our team is inspired to deliver meaningful innovation to more patients globally." With the stock now up more than 100% over the past year, however, I'd wait for some of the turnaround excitement to fade before buying 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.