I must have misunderstood. So they are not expanding testing. Listening to Agenda-Free give his take.
According to @lookner, this is a case not from travel, unknown origin.
New Case of Novel Coronavirus in Northern California: CDC
https://www.nbcbayarea.com/news/california/new-case-of-novel-coronavirus-in-northern-california-cdc/2242792/?_osource=SocialFlowTwt_BAYBrand