Brainshark Inc. has signed a long-term 66,000-square-foot lease at Stone Brook Office Park in Waltham to expand its headquarters.

JLL Managing Director Alex Dauria and Senior Vice President Brendan Cohn negotiated on behalf of the tenant. Executive Vice President James Elcock and Senior Vice President John Carroll III of Colliers International represented the park’s owner Clarion Partners. JLL Construction completed the build-out of new office space and a conference center.

JLL Construction coordinated with project team members CB Richard Ellis, DBW+A Architects and Cosentini Engineers on the 15,000-square-foot build-out and design of the new expansion space. The collaborative space on the first floor of building 2A includes an open concept office area for engineering, conference rooms and perimeter offices. JLL’s team was comprised of Superintendent Steve Pizzuto, Construction Manager Josh Berman and Senior Vice President William Mack.

Stony Brook Office Park is a four-building, 270,000-square-foot first class office park.

Brainshark provides web- and mobile-based training designed to improve companies’ sales and productivity.