Just two data points, but the houses we've seen go up for sale in our neighborhood near Menlo Park were mobbed and went in a week. Prices were higher than I expected, as someone who has been watching the market. Both require massive ($200k+) renovations and/or retrofitting.
Having seen this, and with the coming IPOs, I'd guess prices will continue to trend upward.
I think it will largely depend on how the new stocks perform. The early employees, senior engineers and upper management are probably already pulling in large enough salaries where they could afford to buy if they wanted to. But newer employees (last 3-4 years), HR, sales, etc.. might not have enough appreciation in their options to move the needle much in this housing market ($400k-$500k windfall does not go nearly as far as it used to, and that is probably on the high end for the median employee). This is somewhat due to the fact that these companies have had sky high valuations for so long (Uber was valued at $40B in 2014, projected to go public at $100-120B, so only 3x in 5 years).
Having seen this, and with the coming IPOs, I'd guess prices will continue to trend upward.