ACCOUNTS RECEIVABLE

9 Months Ended

Sep. 30, 2014

Receivables [Abstract]

ACCOUNTS RECEIVABLE

3. ACCOUNTS RECEIVABLE

The Company’s accounts receivable primarily arise from government research contracts and other grants. They are generally stated at invoiced amount and do not bear interest. Because the accounts receivable are primarily from government agencies and historically no amounts have been written off, an allowance for doubtful accounts receivable is not considered necessary. As of September 30, 2014 and December 31, 2013, the accounts receivable balance included unbilled receivables of $2.5 million and $2.4 million, respectively. Approximately $2.4 million of the unbilled receivables as of September 30, 2014 are subject to government audit and will not be collected until the completion of the audit.