In this sample, the date ranges from Jan 15, 2017 - Dec 20, 2017 have been set. All the other dates are out of range and restricted to set or select.
DateRangePicker has min and max supports to restrict the user to select a value from the given range. Only the values in this range will be enabled. In this sample, we have specified min range as Jan 15, 2017 and max range as Dec 20, 2017. User will be able to select the values between this range only. More information on the DateRangePicker min/max support can be found in the documentation section.