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 Rosetta Resources (Nasdaq: ROSE) surged more than 15% Monday after several analysts upgraded the oil and gas company following its quarterly results.

So what: Although Rosetta's first-quarter profit of $11 million came in below analyst expectations, management's increased production guidance -- it now expects to produce between 155 and 165 MMcfe/d for the full year -- is probably what has Wall Street smitten. Investment firm Cannacord Genuity was particularly bullish and placed a $53 price target on the stock, which represents about a 30% premium to its Friday closing price.

Now what: Don't let today's surge keep you from looking into the shares. With Rosetta's Eagle Ford shale play continuing to perform solidly and its asset divestiture program now complete (cash is already up $40.3 million year-to-date), the company seems in a reasonable position to, in Chairman and CEO Randy Limbacher's words, "deliver double-digit growth into the future." More importantly, with a PEG ratio of less than 1, that growth also seems reasonably priced.

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