Most listings are in the $0's per square foot per year. The Tamalpais-Homestead Valley submarket is seeing a decline in rates. In the last 3 months, the median rate fell $45 per sqft per year. That's a 100% decline in rent.
In the last 90 days, 0 listings have been posted online, which means listings most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About NaN% of the listings in the Tamalpais-Homestead Valley are subleases, so you will probably need to sign a longer term lease with the landlord directly. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around sqft.