California Code, Business and Professions Code - BPC § 22372

(a) Every contract for invention development services shall be in writing and shall be subject to the provisions of this chapter. A copy of the written contract shall be given to the customer at the time he signs the contract.

(b) If one or more subsequent contracts are contemplated by the invention developer in connection with an invention, or if the invention developer contemplates performance of services in connection with an invention in more than one phase with the performance of each phase covered in one or more subsequent contracts, the invention developer shall so state in a writing and shall supply to the customer such writing together with a copy of such contract or a written summary of the general terms of each and every such subsequent contract, including the amount of any fees or other consideration required from the customer, at the time the customer signs the first contract.