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 photovoltaic manufacturer ReneSola (NYSE:SOL) have fallen 20% today after the company released its third-quarter earnings report.

So what: Revenue jumped 92.2% from a year ago to $419.3 million and came in well ahead of the $360.7 million estimate. But net loss was $200.3 million, or $2.23 per ADS, which was far larger than the estimated loss of $0.22. 

Now what: The real story here is that ReneSola tried upgrading a polysilicon factory last year in hopes of lowering costs and improving quality. That effort failed and management abandoned it last quarter, sucking up a $194.7 million impairment along the way. Other than that, the quarter was great.

What worries me is that gross margin was only 8.1% last quarter, and management expects a 9%-11% margin for the fourth quarter. That's well below the best in the industry and will keep me from buying today's drop.

Fool contributor Travis Hoium 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.