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 low-pollution power plant manufacturer FuelCell (Nasdaq: FCEL) soared 25% today after its quarterly results easily topped analyst expectations.

So what: The results were so good -- revenue rose 65% to $31.2 million while backlog stands at a record $231 million -- that Wall Street can't help but anticipate even stronger demand to come. Shares of FuelCell had been punished about 50% since the start of the year, but by generating its first quarterly gross margin, investors might finally be seeing the proverbial light at the end of the tunnel.

Now what: Expect the positive momentum to continue in the short run. "We are executing our revenue growth plan and benefiting from operating leverage that is driving down costs," CEO Chip Bottone said. For more conservative Fools, FuelCell's much larger, dividend-paying rival Cummins (NYSE: CMI) might be the safer long-term opportunity.

Interested in more info on FuelCell? Add it to your watchlist.