This information is from an article dated today on the Japanese tech site BroadBand Watch
The controller, while using Bluetooth and therefore being wireless, needs to be connected once to the machine by USB cable prior to use so that the machine can detect the cable (pairing process). This process will be necessary every time the console is powered off then on
The lithium battery inside the controller is also recharged using USB connection. Approx. 2.5 hours of recharging is required for a maximum of about 30 hours of play. The controller can be used even if the battery runs out of power by connecting it to the console (USB). However, as the battery cannot be replaced once it becomes unusable (ceases to recharge), the controller has to be replaced or sent for repairs.