AFAIK, the maximum incubation time is 28-30 days, but anything over 14 days is rare.
http://www.freerepublic.com/focus/bloggers/3826909/posts?page=1
from link:
Dr. Paul Auwaerter, the Clinical Director for the Division of Infectious Diseases at Johns Hopkins University School of Medicine [finds]: If you have a COVID-19 patient in your household, your risk of developing the infection is about 10%….If you were casually exposed to the virus in the workplace (e.g., you were not locked up in conference room for six hours with someone who was infected [like a hospital]), your chance of infection is about 0.5%
According to Dr. Auwaerter, these transmission rates are very similar to the seasonal flu.
As to asymptomatic spread:
The majority of cases see symptoms within a few days, not two weeks as originally believed.
This is great news! (for most of us - people who don't work in a hospital...