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 multimedia semiconductor designer Trident Microsystems (Nasdaq: TRID) fell as much as 19% after the company lowered its expectations for fourth-quarter revenue.

So what: Trident's previous guidance for the fourth quarter was for revenue of $130 million to $140 million and a non-GAAP operating loss of $4 million to $8 million. According to the updated guidance, the actual results won't even sniff the previous expectations. The company now calls for revenue of $115 million to $120 million and a non-GAAP operating loss of $18 million to $22 million. In its statement, the company blamed weaker-than-expected sales to both TV and set-top box customers.

Now what: It doesn't sound like the fourth quarter was a fluke: Trident also said that similar customer trends would hit the first-quarter results even harder. Though the company has recently faced losses and cash burn, there have been hopes that it could turn things around. The company does still sport a debt-free balance sheet with a considerable amount of cash, but with the prospect of more potholes, this stock seems as speculative as ever.

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