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 hospital software specialist MedAssets (Nasdaq: MDAS) climbed as much as 10% in intraday trading Monday on news that Director Bruce Wesson bought 24,000 common shares last week at a price of $9.35-$9.38.

So what: As legendary investor Peter Lynch famously wrote, "Insiders might sell their shares for any number of reasons, but they buy them for only one: They think the price will rise." Given the relatively large size of the purchase, investors have good reason to interpret the disclosure as a pretty good buy signal.

Now what: Don't let today's pop keep you from looking into the stock. Even with today's rally, MedAssets shares are still down more than 50% year-to-date and sport a cheapish forward P/E of about nine. Fools know never to follow insiders blindly into a stock, but Wesson's big buy seems to confirm that the stock represents at least a decent bargain opportunity.

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