If the employee gave 3 days notice or more, final pay is due on the last day of employment. If they gave less, final pay is due within 72 hours.
Penalties for late pay can be that you end up paying the employee an extra day's pay for every day late. The CA DOL does not fool around when it comes to late pay. And in my experience with the CA DOL, they automatically take the employee's position over the employer until or unless the employer is proved categorically to be in the right, and even then it is with great reluctance that they let the employer off the hook. So it would be greatly to your benefit to pay the employee ON TIME.
Two things I am tired of typing: 1.) A wrongful termination does not mean that you were fired for something you didn't do; it means that you were fired for a reason prohibited by law. 2.) The above answer, whatever it is, assumes that no legally binding contract or CBA expressly says otherwise. If it does, the terms of the contract apply.