Note that this is only a non-reportable transfer incident to divorce if the transfer was performed trustee-to-trustee, without the money ever passing through your hands or your ex-wife's hands. Note that if you received a check payable to your Roth IRA that you then forwarded to your Roth IRA custodian, while the check passed through your hands, the money did not.
However, you said that you "received cash" and put the money in your own Roth IRA, implying that a distribution was made to your ex-wife who gave you the money and a contribution was made by you to your Roth IRA. Under these circumstances, this would be a Roth IRA distribution reportable by your ex-wife and a new regular contribution by you. The amount contributed by you in excess of $5,500 would be an excess contribution.
