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 simulation software maker ANSYS (NASDAQ:ANSS) plunged as low as 10% today after its quarterly revenue and guidance missed Wall Street expectations.

So what: ANSYS' third-quarter EPS managed to top estimates, but a miss on the top line -- $199.8 million versus the consensus of $202 million -- coupled with downbeat guidance is triggering concerns over slowing growth going forward. Management blamed lengthening procurement cycles due to the weak economy for the outlook cut, giving momentum-seeking investors plenty of reason to exit the previously strong stock.

Now what: Management now sees full-year 2013 EPS of $3.00 to $3.12 on revenue of $885 million to $910 million, well below Wall Street's view of $3.22 and $930.4 million. "Customer interest remains strong, but we expect these macro-economic challenges and longer sales cycles to continue through the remainder of the year and into the next," said CEO Jim Cashman. "At the core of the business, the long-term remains driven by customer reliance on our solutions to help fuel their internal innovation." However, when you couple the short-term headwinds facing ANSYS with the stock's still-lofty 30-plus P/E, I'd wait for a much bigger pullback before buying into that bullishness.

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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.