NEW YORK ( TheStreet) -- Shares of Cardiovascular Systems (Nasdaq: CSII) were gapping down Friday morning with an open price 10.4% lower than Thursday's closing price. The stock closed at $10.30 Thursday and opened today's trading at $9.23. The average volume for Cardiovascular Systems has been 137,400 shares per day over the past 30 days. Cardiovascular Systems has a market cap of $173.3 million and is part of the health care sector and health services industry. Shares are down 11.7% year to date as of the close of trading on Thursday. Cardiovascular Systems, Inc., a medical device company, focuses on developing and commercializing minimally invasive treatment solutions for vascular disease. TheStreet Ratings rates Cardiovascular Systems as a sell. The area that we feel has been the company's primary weakness has been its disappointing return on equity. You can view the full Cardiovascular Systems 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.