NEW YORK ( TheStreet) -- Shares of DexCom (Nasdaq: DXCM) were gapping down Thursday morning with an open price 24% lower than Wednesday's closing price. The stock closed at $9.80 Wednesday and opened today's trading at $7.45. The average volume for DexCom has been 571,500 shares per day over the past 30 days. DexCom has a market cap of $632.9 million and is part of the health care sector and health services industry. Shares are down 28.2% year to date as of the close of trading on Wednesday. DexCom, Inc., a medical device company, engages in the design, development, and commercialization of continuous glucose monitoring systems for people with diabetes in the United States. TheStreet Ratings rates DexCom as a sell. Among the areas we feel are negative, one of the most important has been a generally disappointing historical performance in the stock itself. You can view the full DexCom Ratings Report. Get more investment ideas from our investment research center. Interested in other stocks that are gapping down? Get free SMS text alerts sent to you when the action happens by texting DOWN to 95370 or select from multiple alert options.