Don't go here. It's nearly impossible to get anyone on the phone. If you leave a message and miss their callback, you have to call again and wait to be contacted, since nobody answers the phone in real time. I've waited days for them to return my messages. A receptionist told me she typically has 14 calls to return at any time, and can't answer the phone when it rings because she's busy handling patients in the office.
Also, I never waited less than 30 minutes past my appointment time before the doctor came into the exam room. I always felt like I was getting vague advice from the doctor, with no follow-up plan. I always had to ask clarifying questions, and ask what to do next, and when. I never felt sure that he knew what he was talking about.
I had an ultrasound done and waited a week before calling Cornerstone to see if the doctor could tell me if I was ok or not. The male receptionist told me the doctor had reviewed it but he wasn't sure what the doctor "wanted him to say to me about it." I tried to be polite and just said ok, but he made it sound like there was something bad that showed up in my ultrasound, and I was concerned. I waited several hours and called back at 12:30, and was told that the doctor had not looked at it yet. Several hours later I received a call back telling me my scan was negative and I was fine, despite being made to think there was some bad news all day.
The last straw for me was when my prescriptions had to be renewed. They kept submitting them to various Walgreens retail stores in Arizona instead of the Walgreens mail order facility in Arizona, where I had been getting them from just fine. I was told that my doctor's office would have to resolve it on their end.
When I called the doctor's office, the male who occasionally answers the phone basically said they would resubmit the prescription by trying another Arizona Walgreens location and hoping that was the right one. They messed this part up too, and I just ended up getting a call from another Walgreens retail store telling me they think they received my prescription in error. Now I have an email from Walgreens telling me I'm out of refills and they're unable to contact my doctor's office to get it corrected. Of course they can't. Nobody answers the phone. I'm going to run out of my prescriptions before this is resolved, I'm sure of it.
Read the reviews for this place on Healthgrades.
Save yourself a lot of trouble and go to a real doctor's office.