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 small-cap biotech Delcath Systems (Nasdaq: DCTH) popped more than 10% in intraday trading, as takeover rumors may have sparked investor excitement.

So what: The unconfirmed rumor has drug giant Bristol-Myers Squibb (NYSE: BMY) offering $15 for Delcath, representing a spectacular premium to its current price. While takeover talk is certainly cheap, it's widely known that Bristol, along with Onyx Pharmaceuticals (Nasdaq: ONXX), have been yearning to get into the liver cancer space.

Now what: Fools know never to jump into a stock on takeover speculation alone. But with Delcath recently validating positive trial results for its drug delivery system, as well as raising about $35 million in a secondary offering, the stock does sport some serious hidden potential. If Delcath gets its PHP system approved by mid-2011, like its CFO expects, today's speculation-fueled surge will likely be a drop in the bucket.

Update: On Friday, Oct. 8, Delcath shares moved an additional 14% in intraday trading on no new news.

Fool contributor Brian Pacampara owns no position in any of the companies mentioned. Try any of our Foolish newsletter services free for 30 days.

True to its name, The Motley Fool is made up of a motley assortment of writers and analysts, each with a unique perspective; sometimes we agree, sometimes we disagree, but we all believe in the power of learning from each other through our Foolish community. The Fool has a disclosure policy.