CDCE6214-Q1: SECREF_P/N pins floating when not used/not connected?

Tool/software:

Dear Madam or Sir,

I am planning to use the CDCE6214-Q1.

I do not plan to use the secondary reference clock inputs: SECREF_P/N.

Can I leave these pins unconnected and floating, or should I bias/connect them to some external pull-up or pull-down resistors?

Best regards,