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 Raptor Pharmaceuticals (NASDAQ:RPTP), a biopharmaceutical company focused on developing therapies to treat a number of unmet diseases, including Huntington's disease and nonalcoholic steatohepatitis, fell as much as 23% after reporting its fourth-quarter results after the closing bell last night.

So what: For the quarter, Raptor reported net product sales of Procysbi, its FDA-approved treatment for nephropathic cystinosis, of $10.2 million. Net loss, excluding one-time costs, came in at $11.8 million, or $0.19 per share, as the company dealt with higher research and development costs associated with its clinical studies. By comparison, Wall Street anticipated a smaller loss of just $0.16 per share. The truly damning factor was its guidance. Raptor is currently projecting $55 million-$65 million in Procysbi product sales in fiscal 2014 whereas Wall Street expected $69.2 million in Procysbi sales.

Now what: With Raptor shares having more than tripled following the approval of Procysbi last year, the expectation from investors is that Raptor would be marching closer to profitability and that revenue would soar. Raptor's guidance would seem to indicate that things are moving in the right direction but at a much slower pace than Wall Street wanted to see. Even after today's drop, Raptor still seems a bit frothy to me given Procysbi's peak sales potential. For now, I'd suggest hunkering down on the sidelines and waiting for the Raptor pipeline and bottom line to do the talking.

Raptor shares have soared over the past year, but even it may struggle to keep pace with this top stock
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Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

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