The valuation basis is cost and includes direct combination costs, but excludes the contingent consideration.
The cost is allocated to the assets acquired and liabilities assumed based on their individual fair values(unless a bargain purchase occurs and then the long-term items may be recorded as amounts less than their fair values)
Goodwill is the excess of cost over the fair values of the net assets purchased.
Acquired in-process research and development is expensed immediately at the purchase date