I'm not sure why this article is focusing on things like whether the reactor can fit on a truck, where you get deuterium, and how many coal power plants it can replace - instead of the actual question which is how they managed to produce a stable exothermal fusion reaction.
As far as I can tell from reading various articles (including the Aviation Week article linked elsewhere in the comments), they haven't. The expectation is that they will have a prototype in five years. For that reason, I wouldn't get too excited about this.
