DexCom Shares Plunged: What You Need to Know

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 DexCom (NAS: DXCM) , which is developing an ambulatory glucose monitor for diabetes sufferers, closed down more than 18% after giving full-year guidance that may have disappointed investors. (We''ve seen it happen before.)

So what: Second-quarter results appear to have come in above estimates, though it's difficult to tell exactly what the Street was looking for. DexCom booked an $0.11-per-share loss on $21.4 million in overall revenue, $15.2 million of which was related product sales. Analysts were expecting a $0.12-per-share loss and $20.8 million in revenue. Whether they were counting all revenue or just product revenue isn't clear, though I suspect the latter.

Now what: Why? In reiterating guidance during yesterday's call with analysts, management called for $67.5 to $72.5 million in just product revenue for the full year. Wall Street wanted $78.1 million of ... some sort of revenue. Regardless, judging by the size of the selloff, this looks like a miss. Do you agree? Disagree? Weigh in using the comments box below.

Interested in more info on DexCom?Add it to your watchlist.

At the time thisarticle was published Fool contributorTim Beyersis a member of theMotley Fool Rule Breakersstock-picking team. He didn't own shares in any of the companies mentioned in this article at the time of publication. Check out Tim'sportfolio holdingsandFoolish writings, or connect with him onGoogle+or Twitter, where he goes by@milehighfool. You can also get his insightsdelivered directly to your RSS reader.Try any of our Foolish newsletter servicesfree for 30 days. We Fools don't all hold the same opinions, but we all believe thatconsidering a diverse range of insightsmakes us better investors. The Motley Fool has adisclosure policy.

Copyright © 1995 - 2011 The Motley Fool, LLC. All rights reserved. The Motley Fool has a disclosure policy.