 USANA Health Sciences, Inc. NYSE:USNA was the target of a large decrease in short interest in the month of April. As of April 15th, there was short interest totalling 1,870,000 shares, a decrease of 8.8 from the March 31st total of 2,050,000 shares. Based on an average daily volume of 249,000 shares, the days-to-cover ratio ... 