In general the goal is for an exothermic reaction. It should be possible. Perpetual Motion Machine would be one that could sustain itself without fuel. This one can't. It has to use heavy water and helium to form the plasma. To be an actual perpetual motion machine, the system would have to create enough energy to be converted into hydrogen (E=MC^2 and all), then feed itself with the new fuel. Even at 8 times the energy output, they can't get enough energy to create parts of the fuel.

They might be a little foolish expecting (and suggesting they can deliver) net positive fusion reactors in three years, but what they're doing is solid physics. It's a high risk, high reward investment and I'm glad it's happening even if I don't think it's likely to work because someone _soon_ is going to be successful in creating a commercially viable fusion reactor, and more separate groups trying makes the chances of success higher.