Default Nexus 4 Cracked Screen Help Backing Up Data

Hello all,

I have an LG NExus 4 which has a cracked screen. The top half of the screen detects touch input but the bottom half does not. Which means I cannot press "Enter" after keying in my passcode for the lockscreen. I have some data I would like to backup. I ran the adb devices command. It returns a serial number but also it says unauthorized. Do you think you could help me backup data?

Appreciate any help you can provide.