For UFT v11.5x/12.0x, it's not possible. See here: https://eyeontesting.com/questions/17408/can-you-set-an-idle-timeout-on-uft-120x-to-release.html
For UFT v14.03 and AutoPass License Server (APLS) 9.3.2 and above:
**1)** Navigate to the license server data configuration folder and edit the UFT configuration file:
*Default location and file name for APLS 9.3.x:*
> %ProgramData%HPHP AutoPass License ServerAutoPassLicenseServerdataconfHPE UFT.xml
Note: be careful to only modify **HPE UFT.xml**
*Default location and file name for APLS 10.7 (new install only):*
**2)** Add the following key before the `` tag closes in the UFT configuration file:
Change the value as needed (this example is for a 15 minute timeout on UFT after an idle time of no keyboard or mouse interaction.
Full file example:
**3)** Restart the AutoPass license server Windows Service for your changes to take effect.