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 Rofin-Sinar Technologies (Nasdaq: RSTI) have plunged today by as much as 16% after the company reported second-quarter earnings and a gloomy outlook.

So what: Revenue totaled $129.4 million, and earnings per share ended up at $0.28. Both fell slightly short of investors' hopes. Consensus estimates had called for $133.2 million in sales and $0.29 per share in profit. CEO Gunther Braun said the weak economic environment from last year has carried into the early part of 2012, hurting results.

Now what: Braun also said demand has begun to recover in the company's machine tool business, as well as in the medical device and solar sectors. Next quarter, expected sales are between $130 million and $135 million, with EPS between $0.27 and $0.30. Those forecasts fall far short of the $144 million in sales and EPS of $0.37 that the Street was looking for.

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Fool contributor Evan Niu holds no position in any company mentioned. Click here to see his holdings and a short bio. The Motley Fool owns shares of Rofin-Sinar Technologies. Motley Fool newsletter services have recommended buying shares of Rofin-Sinar Technologies. The Motley Fool has a disclosure policy. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days.