Shareholders in Lululemon Athtletica (LLL) have seen enough, literally and figuratively. A group of investors has banded together to sue the apparel company for securities fraud, claiming the company knowingly made its yoga pants too thin, despite their denials. Because its pants are so sheer, they become almost transparent when stretched. That???s made sales fall off a cliff, taking share price with it. And Lululemon investors aren???t standing for it any more. If you???re currently holding onto the company???s shares, you might want to consider selling before it gets really ugly — unless you want to join the fray.