I have faced with some strange behaviour of the touchpad on 16.04
Sometimes(after 5-6 hours of uptime) it just stops working until the reboot, also I realized that frequency of this also affected by the kernel version
so it usually happened in the first hour of uptime in 4.15.0-45-generic and after 5-6 hours in 4.15.0-45-generic

kkhamitov@kkhamitov-nix:~$ apt-cache policy xserver-xorg-input-synaptics
xserver-xorg-input-synaptics:
Installed: (none)
Candidate: 1.8.2-1ubuntu3
Version table:
1.8.2-1ubuntu3 500
500 http://mirror.yandex.ru/ubuntu xenial/main amd64 Packages

xorg:
Installed: 1:7.7+13ubuntu3.1
Candidate: 1:7.7+13ubuntu3.1

Xorg log
https://pastebin.com/LkhzCDW3