This response is based on the information provided.  We suggest you discuss with your contracting team, program manager and/or legal department as appropriate. 

We are not aware of the IDR contract type.  For the purpose of responding to this question will are assuming IDR refers to a Requirements contract.  FAR subpart 16.5 thoroughly explains the applicability and differences of each type.

FAR 16.504 describes IDQ contracts as requiring a minimum order and setting a maximum.  You may state the maximum, or ceiling, in either units or dollars.  You will need to read the section thoroughly to note all requirements.

FAR 16.503 describes requirements contracts in detail.  When using a requirements contract, the government agrees to buy all requirements from that contractor over the ordering period, usually a year.  The government is not bound to order any amount during the ordering period, unless it specifically negotiates to do so, but may not order this requirement from another company during the ordering period unless the company contracted states this order is beyond its capability to meet.  You will need to read the section thoroughly to note all requirements.

We recommend reading FAR subpart 16.5 closely for additional information