Cal. Bus. & Prof. Code § 22383

Any contract for invention development services which does not comply with the applicable provisions of this chapter shall be void and unenforceable as contrary to public policy, provided that no contract shall be void and unenforceable if the invention developer proves that noncompliance was unintentional and resulted from a bona fide error notwithstanding the use of reasonable procedures adopted to avoid any such errors and makes an appropriate correction.