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 network security specialist Palo Alto Networks (NYSE: PANW) sank 10% today after its quarterly revenue disappointed Wall Street.

So what: Palo Alto's fourth-quarter earnings managed to top estimates, but revenue growth of "only" 88% -- compared to 100%-plus growth in the three previous quarters -- is triggering concerns over slowing growth going forward. Of course, given the stock's big run leading up to the earnings release, it's no surprise that investors are choosing to take some profits off the table.

Now what: Management now sees current-quarter adjusted EPS of $0.03 on revenue of $80 million to $84 million, versus Wall Street's estimate of $0.03 and $80 million, respectively. "Our unique and innovative approach to network security resonates with enterprises around the world as they look for ways to protect their networks and safely enable the explosion of application use driven by productivity trends in cloud computing, SaaS, mobility and social networking," said CEO Mark McLaughlin. With Palo Alto still trading at a very wide price-to-sales premium to fierce rivals like Check Point Software and Cisco Systems, however, I'd wait for a larger margin of safety before buying into those tailwinds.

Interested in more info on Palo Alto Networks? Add it to your watchlist.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.