Segment, Customer Concentration and Geographical Information - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2014 Location Customer Business_Unit	Mar. 31, 2013 Location Customer
Revenue, Major Customer [Line Items]
Number of primary business units	2
Number of customers that contribute more than 10% of revenue.	3	3
Number of geographic locations	3	3
Credit Concentration Risk [Member] | Accounts receivable [Member] | Sprint, Verizon Wireless and Fast Spring [Member]
Revenue, Major Customer [Line Items]
Percentage of concentration	90.00%	78.00%