Never heard of it. But what does IDO stands for?
Initial DEX Offering
That just a decentralized exchange, there is no new things about these even on IDEX & EtherDelta a few years ago we doing this scheme no matter ICO, IEO, and other things the main target only for sell their token.
So, IMO there is nothing different at all about IDO, IEO or ICO dont give some sh*t too about them ~LOL.