2011 and 2010, respectively. Historically, substantially all of our customers, including customers from acquired companies, renew their software license updates and product support contracts when the contracts are eligible for renewal and we intend to focus our efforts on renewing acquired hardware systems support contracts. To the extent software support or hardware systems support contracts are renewed, we will recognize the revenues for the full value of the support contracts over the support periods, the substantial majority of which are one year.

In connection with a business combination, we estimate costs associated with restructuring plans committed to by our management. Restructuring costs are typically comprised of employee severance costs, costs of consolidating duplicate facilities and contract termination costs. Restructuring expenses are based upon plans that have been committed to by our management, but may be refined in subsequent periods. We account for costs to exit or restructure certain activities of an acquired company separately from the business combination. These costs are accounted for as one-time termination and exit costs pursuant to ASC 420, Exit or Disposal Cost Obligations . A liability for a cost associated with an exit or disposal activity is recognized and measured at its fair value in our consolidated statement of operations in the period in which the liability is incurred. When estimating the fair value of facility restructuring activities, assumptions are applied regarding estimated sub-lease payments to be received, which can differ materially from actual results. This may require us to revise our initial estimates which may materially affect our results of operations and financial position in the period the revision is made.

For a given acquisition, we may identify certain pre-acquisition contingencies as of the acquisition date and may extend our review and evaluation of these pre-acquisition contingencies throughout the measurement period (up to one year from the acquisition date) in order to obtain sufficient information to assess whether we include these contingencies as a part of the purchase price allocation and, if so, to determine their estimated amounts.

If we determine that a pre-acquisition contingency (non-income tax related) is probable in nature and estimable as of the acquisition date, we record our best estimate for such a contingency as a part of the preliminary purchase price allocation. We often continue to gather information for and evaluate our pre-acquisition contingencies throughout the measurement period and if we make changes to the amounts recorded or if we identify additional pre-acquisition contingencies during the measurement period, such amounts will be included in the purchase price allocation during the measurement period and, subsequently, in our results of operations.

In addition, uncertain tax positions’ and tax related valuation allowances assumed in connection with a business combination are initially estimated as of the acquisition date and we reevaluate these items quarterly with any adjustments to our preliminary estimates being recorded to goodwill provided