The range varies greatly depending on the circumstances. In my office I have gotten up to 1000 ft., but the situation was that I was in direct line of sight from the phone with no interference.
On other occasions, like the OP, I could not get 40-50 ft without disconnecting. This usually happens when there are a lot of walls, stairs, or glass blocking the line of sight from the Gear to the phone. As a general rule I get between 100-150 ft.