Lululemon Athletica Inc (NASDAQ:LULU) shares fell about 10% in after-hours trading on Thursday after the athletic apparel retailer issued guidance pointing to a potential decline in sales, despite reporting first-quarter results that narrowly topped Wall Street expectations. The company projected second-quarter revenue between $2.45 billion and $2.475 billion, which would represent a year-over-year decline of 3% to 2%.