An input device (100) for a computing device (150) is provided, such as a data glove. The input device (100) comprises motion sensor(s) (103) configured to be worn on a fingertip or fingertips of a user, and actuator(s) (104, 114) configured to restrict motion of the fingertip(s) to be within a three-dimensional shape. The input device (100) is operative to track a position of the fingertip(s) using the motion sensor(s) (103), provide the tracked position as user input to the computing device (150), determine whether the computing device requires user input from the fingertip to be within the three-dimensional shape, and in response thereto, activate the actuator(s) (104, 114) configured to restrict motion of the fingertip(s) to be within the three-dimensional shape if the computing device (150) requires user input from the fingertip(s) to be within the three-dimensional shape. Thereby, the user is prevented from moving his/her fingertip(s) to a position in space which renders user input which is not accepted by the computing device (150) receiving the user input.