$ATRC is one of biggest losers #stocks today. read more:

AtriCure, Inc. (symbol: ATRC) was one of the worst losers of the trading
day today (2015-10-05), losing -8.82%. The number of shares that changed
hands was 1,981,470, or about 10 times the average daily volume in the
stock.
The closing price was $20.47, amounting to a market cap of $584,150,000,
about -27.28% off the highest price in the last 12 months. The stock has
been trading at a range between $13.19 and $28.15.
ATRC is in the Medical/Dental Instruments industry, part of the Health Care
sector. It first went public in 2005.