Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk primarily consist of cash and cash equivalents placed with high credit quality institutions and accounts receivable due from customers. MRV evaluates the collectability of accounts receivable based on a combination of factors. If the Company becomes aware of a customer's inability to meet its financial obligations after a sale has occurred, the Company records an allowance to reduce the net receivable to the amount that it reasonably believes to be collectable from the customer. For all other customers, the Company records allowances for doubtful accounts based on the length of time the receivables are past due, the current business environment, and historical experience. If the financial conditions of MRV's customers were to deteriorate or if economic conditions worsen, additional allowances may be required in the future. Accounts receivable are charged off at the point they are considered uncollectible.

The following table summarizes the changes in the allowance for doubtful accounts during the three months ended March 31, 2014 (in thousands):



	Three months ended
	March 31, 2014
Balance at beginning of period		$2,183
Charged to expense	(77		)
Write-offs	—
Foreign currency translation adjustment	(3		)
Balance at end of period		$2,103