Accounts Receivable

6 Months Ended

Jun. 30, 2011

Accounts Receivable

Accounts Receivable

Note 3. Accounts Receivable

Accounts receivable are stated at invoiced amount and do not bear interest as they are due within 12 months. Because a majority of accounts receivable are from the U.S. government and historically no amounts have been written off, an allowance for doubtful accounts receivable is not considered necessary. The accounts receivable balance included $4.6 million and $3.2 million of receivables that were unbilled at June 30, 2011 and December 31, 2010, respectively.