William K. O'Brien has served as a director since November 2008. O'Brien served as executive chairman at Enterasys Networks, a public technology company, from 2003 until his retirement in 2006. He served as chief executive officer of Enterasys from April 2002 until March 2004 and as a member of the board of directors of Enterasys from 2002 to 2006. Prior to Enterasys, O'Brien worked for over thirty years at PricewaterhouseCoopers LLP, where he served in a number of roles including chief operating officer of the former Coopers & Lybrand, with responsibility for the audit, tax and financial advisory components of the U.S. business; managing partner for the Boston office; and a global managing partner of PricewaterhouseCoopers. He currently serves on the board of directors of Mercury Computer Systems, Inc., a leading commercial provider of secure processing subsystems for a wide variety of critical defense and intelligence programs. He has previously served on other public company boards.He is a graduate of Bentley College.