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 Compuware (Nasdaq: CPWR) are plunging today by as much as 10% after the software maker reported second-quarter results.

So what: Compuware brought in sales of $260.7 million, which yielded $0.10 earnings per share. The Street was expecting $249.5 million revenue and $0.09 in earnings per share. Despite the top- and bottom-line beats, the company's guidance has spooked investors.

Now what: The company lowered its full-year outlook, attributing the drop to a stronger dollar versus the euro and slower-than-expected growth in application performance management services. The soft guidance has sent investors fleeing despite the fact that it boasted that Gartner now places the company in the "leaders" quadrant for application performance monitoring. The guidance game is a tough game to play, and it can punish companies even when they top expectations.

Interested in more info on Compuware? Add it to your watchlist by clicking here.

Fool contributor Evan Niu holds no position in any company mentioned. Click here to see his holdings and a short bio. 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.