In Oracle VM VirtualBox running Ubuntu 16.04 under Windows 10, I have trouble connecting USB devices (which have problems under Windows but not Linux) for emulation.
A useful workaround was to go to Devices > USB > (the particular device you wish to connect), then physically disconnect (remove power) and reconnect the particular USB device, and it now shows up when lsusb is run.
A useful workaround was to go to Devices > USB > (the particular device you wish to connect), then physically disconnect (remove power) and reconnect the particular USB device, and it now shows up when lsusb is run.