The abbreviation IDO stands for Initial DEX Offering. This is very similar to an ICO but still slightly different. With an ICO, you have different forms: via a smart contract, an agreement contract, or via a launchpad of a centralized exchange. When the tokens are tradable depends on the listing on an exchange. An IDO also involves raising money for a new coin but goes through a DEX. In this way, the tokens are tradable almost immediately