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 Limelight Networks (NASDAQ:LLNW) were down 17.5% at Thursday's market close. At worst, the stock temporarily fell as far as 23% below Wednesday's closing price. A court decision filed Thursday morning put an end to a nearly decade-spanning patent infringement lawsuit between Limelight and Akamai Technologies (NASDAQ:AKAM), and Akamai came out on the winning end.

So what: A 10-judge panel at the U.S. Court of Appeals for the Federal Circuit in the District of Columbia unanimously agreed that Limelight owes Akamai about $45.5 million in damages. This case has bounced all the way to the Supreme Court and back again. Today's decision effectively reaffirms an earlier District Court verdict, and as I understand it, Limelight has effectively run out of appeals at this point.

Now what: The two patents at issue were developed by the Massachusetts Institute of Technology and offered to Akamai under an exclusive license. They deal with crucial technology and business aspects of running a global content delivery network, which happens to be the very core of what both companies do for a living.

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Image source: Limelight Networks.

The federal panel of judges still has to settle the finer details of the verdict. The $45.5 million verdict from 2009 has been overturned, revived, and now affirmed, but the final sum might differ substantially from the original damages. This is six years later, leaving plenty of leeway for time-based adjustments.

Assuming that the verdict lands in roughly the same neighborhood, a $45 million payment would amount to 27% of Limelight's total sales across the last four quarters, or more than half of the company's cash reserves. For sector giant Akamai, the same payment would work out to roughly 2% of the much larger company's $2.1 billion of trailing sales or 7% of Akamai's current cash balance.

This is a very important verdict for Limelight, and a painful one, too. For Akamai, it's just a drop in the ocean. The lawsuit was filed in a different era, when Limelight had an outside shot at threatening Akamai's core business. Those days are past. For Akamai, this final payoff is really more about the principle of enforcing its patented ideas than about collecting the money.

Anders Bylund has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.