If it's temporarily idle you continue depreciation. See IRS Pub 946 (2019) page 7 column 2:
Continue to claim a deduction for depreciation on property
used in your business or for the production of income
even if it is temporarily idle (not in use). For example, if
you stop using a machine because there is a temporary
lack of a market for a product made with that machine,
continue to deduct depreciation on the machine.