The next round of acceptances won't be sent out until January 2nd(?), which will be 30 days after the 1st round. Anyone from that 1st round that declined the offer, will now have their seat opened to the 2nd wave of acceptances.
After this, the 3rd round is 15 days after the 2nd round, so should be January 17th(?). After this date, offers are made on a rolling basis until the class is full.
** (?): Because I don't work in admissions, these dates are just speculations based on what I remember from my application year.