It looks like two funds, MFS, a mutual fund and Visium, a hedge fund have taken a 5% or more interest.
Yahoo lists the major funds that own this stock. Both MFS and Visium apparently doubled their holdings recently. It appears that they must file within 10 days if the acquisition puts them over 5% ownership, which these did. So, these two funds purchased substantial additional stakes in the company in the last ten days or so. Sounds like good news to me.