in any period is dependent on our progress toward completion of projects in progress. Significant management judgment and discretion are used to estimate total direct labor hours. Any changes in or deviations from these estimates could have a material effect on the amount of revenue we recognize in any period.



        Royalty revenue is recognized related to the distribution or sale of products that use our technologies under license agreements with third parties.  We recognize royalty revenue upon receipt of a confirmation of earned royalties and when collectability is reasonably assured from the applicable licensee.

 

Accounts Receivable

 

We maintain an allowance for doubtful accounts receivable for estimated losses resulting from the inability of our customers to make required payments.  Management determines this allowance, which consists of an amount identified for specific customer issues as well as an amount based on overall estimated exposure. Our accounts receivable are highly concentrated and make us vulnerable to adverse changes in our customers businesses, and to downturns in the industry and the worldwide economy.   Our overall estimated exposure excludes significant amounts that are covered by credit insurance and letters of credit. If the financial condition of our customers, the financial institutions providing letters of credit, or our credit insurance carrier were to deteriorate, resulting in an impairment of their ability to make payments, additional allowances may be required that could adversely affect our operating results. This risk is heightened during periods when economic conditions worsen, such as the when the worldwide economy is experiencing a significant downturn. The financial turmoil that affected the banking system and financial markets and increased the risk that financial institutions mighty consolidate or go out of business resulted in a tightening in the credit markets, a lower than normal level of liquidity in many financial markets, and extreme volatility in fixed income, credit, currency and equity markets. There could be a number of follow-on effects from this type of credit crisis on our business, including inability of customers, including channel partners, to obtain credit to finance purchases of our products and/or customer, insolvencies and failure of financial institutions, which could negatively impact our financial results. Furthermore, there can be no assurance that we will be able to continue to obtain credit insurance in the future.



As of January 30, 2011, our allowance for doubtful accounts receivable was $0.8 million and our gross accounts receivable balance was $386.5 million. Of the $386.5 million, $86.0 million was covered by credit insurance and $4.4 million was covered by letters of credit. If the financial condition of our customers were to deteriorate, resulting in an impairment of their ability to make payments, additional allowances may be required and we may have to record additional reserves or write-offs on certain sales transactions in the future. Factors impacting the allowance include the level of gross receivables, the financial condition of our customers and