She will move into a chief technical officer role, while the CEO spot will be filled by Lance Vanden Brook, a onetime Kiva Systems/Amazon executive who was most recently SVP of the energy and industrial group of Pilot Thomas Logistics.

Greiner is best known as the co-founder of Roomba maker iRobot (PJT), where she also served as president and chairman. She later founded CyPhyWorks to develop small, multi-rotor drones for the consumer, commercial, and military markets ― raising over $30 million in venture capital funding, plus some additional cash raised via a Kickstarter campaign. Just recently, the Massachusetts company announced that it received an order for one of its tethered surveillance drones (which can fly for days at a time) from the U.S. Army’s Rapid Equipping Force.

A source close to the situation says that a formal announcement about the CEO swap is forthcoming, and says that Greiner―still the company’s top technologist―had become overextended.

“Helen needed to focus on making sure our drones are as reliable as we need them to be for rather heavy duty applications,” the source says. “We first thought we would bring on a COO but then decided for a CEO that is more commercially- and sales-focused.”

Greiner has not yet returned a request for comment.