I’ve read this article a couple of times and it doesn’t say whether or not he delivered them, electronically or otherwise. If that is the case, then the company should get the death penalty. Cut them out of American business and anyone this technology gets transferred to.
From the story, it seems he transferred over half of the documents to his wife's computer electronically via something called "Air Drop". I think it's reasonable to assume that all data transmitted electronically has been transferred to China by now. This horse is already out of the barn.
The only thing that will deter this sort of crime are lengthy prison sentences with no parole. Five years is not enough. A young person can figure they can chill for five years if there is a couple of million dollars "back pay" on the other side. I see 15 years minimum as a reasonable deterent, perhaps 30 years max.