$ lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 03eb:8a96 Atmel Corp.
Bus 001 Device 003: ID 8087:0a2a Intel Corp.
Bus 001 Device 002: ID 1bcf:28b0 Sunplus Innovation Technology Inc.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Possibly related: the Atmel touchscreen also does not always reconnect after sleep. "sudo rmmod hid_multitouch ; sudo modprobe hid-multitouch" restores that, but reloading hid_magicmouse does not restore the mouse.
Follow-up to #19:
$ bluetoothctl
[NEW] Controller 00:DB:DF:F9:6A:81 newcastle [default]
[NEW] Device 78:CA:39:EB:AF:83 Laptop Magic Mouse
[NEW] Device 48:59:29:54:70:2D Nexus 5
[NEW] Device F8:16:54:9D:4C:3D TIAA-7321BJWL12
[NEW] Device 3B:B6:0A:CE:DB:FE SPBT3
$ lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 03eb:8a96 Atmel Corp.
Bus 001 Device 003: ID 8087:0a2a Intel Corp.
Bus 001 Device 002: ID 1bcf:28b0 Sunplus Innovation Technology Inc.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Possibly related: the Atmel touchscreen also does not always reconnect after sleep. "sudo rmmod hid_multitouch ; sudo modprobe hid-multitouch" restores that, but reloading hid_magicmouse does not restore the mouse.