Poppy, a new Chrome OS device, looks set to be the very first detachable Chromebook. This and other factors point to the fact that Chrome OS may soon begin seeing a deluge of devices in new form factors for the OS, with detachables and tablets quite likely to take the spotlight among them. Aside from the presence of Poppy, suspicion is fueled by comments from Rajen Sheth, Google's director of product for education and enterprise applications in both Chrome OS and Android. According to Sheth, serious work on Chrome OS' touch interface and optimization for other form factors is opening the door for Chrome OS devices to come in all sorts of packages in the near future. Sheth specifically mentioned tablets and detachables, and those statements pair quite nicely with the fact that Google says all Chrome OS devices going forward will have Android app support.
As for Poppy, only a few commits in the Chromium codebase point to it and all that's really known about it at the moment is that it will be based around Intel's Skylake processor architecture, and it will feature a detachable form factor. This is not the first time that code commits in the Chromium project's codebase have mentioned a special detachable UI, but it is the first time that such code has been tied directly to a certain hardware device, all but confirming that the device in question, in this case Poppy, will be a detachable.
Chrome OS tablets have been whispered about before, but there has never been definitive proof that they're coming. The logical leap here is that Sheth's comment and the presence of a detachable UI in Chromium's code mean that Chrome OS tablets are possible, but there is still no confirmed details on any actual Chrome OS tablet devices just yet. According to Sheth, though, tablets are likely on the menu in the future. Since most of the work will have already been done to optimize Chrome OS for tablets once Poppy drops, it's not a stretch to think that manufacturers will take advantage of that work to build tablets with no fuss on the software side.