What moves idea prices?

Here's a sample from a few industries I track, taken over about a 3-day period:



As you can see, the relationship between price change and pressure factors is linear, with approximately 0.1*(U - D1 - D2) determining the magnitude of the change. In other words, if U is 0.9, D1 is 0.4, and D2 is 0.4, then price will increase by 1% on the next drop, as long as there are no ideas sitting on the market.