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 molecular diagnostics company Genomic Health (NASDAQ:GHDX) dropped as much as 21% today after the company reported disappointing third-quarter earnings results.

So what: For the quarter, Genomic reported a 12.5% increase in revenue to $58.6 million and an adjusted profit of $0.11. Revenue figures came in shy of Wall Street's consensus estimate of $59.9 million, while EPS was a saving grace, beating forecasts by $0.06. During the quarter, Genomic delivered 7% more Oncotype DX test results compared to the year-ago period, and it announced positive prostate cancer validation study results that should allow its Oncotype DX to be marketed as a prostate cancer diagnostic test by the first half of 2013.

Now what: What this really comes down to is investors expecting much more in terms of Oncotype DX growth from a company trading at a frothy 83 times forward earnings even after today's large drop. This is a case where the technology makes sense on paper and should eventually become a success, but weak global growth and a relatively young product are creating a melting pot of concerns that will take some time to congeal. I'm perfectly happy watching Genomic Health from the sidelines in the meantime.

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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.