Legal Question in Legal Ethics in California

No. Save all documentation (don't keep important documents like this at your workplace) and when and if you lose your job, you could file a claim with the State Labor Commissioner.

I disagree with Stone. It depends entirely on the terms of the bonus plan and the circumstances of your departure. It is perfectly legal to have a bonus with a retention provision that makes it payable only if you continue employment. In that case, if you quit or are terminated for reasonable cause, you lose the bonus.