Realistically speaking, short of airgapped networks and military-style security, you can't.
It's also much less of a problem than you'd think, since if somebody does walk away with valuable IP and tries to make money with it, they can be sued to oblivion. Employers are also well aware of this, which is why few competitors would want to touch it. See eg. Lewandowski in the Uber v Google case.
It's also much less of a problem than you'd think, since if somebody does walk away with valuable IP and tries to make money with it, they can be sued to oblivion. Employers are also well aware of this, which is why few competitors would want to touch it. See eg. Lewandowski in the Uber v Google case.