Segment Information - Accounts Receivable (Details)	3 Months Ended
	Mar. 31, 2014 Nokia Siemens Networks [Member]	Mar. 31, 2013 Nokia Siemens Networks [Member]	Mar. 31, 2014 Nokia Siemens Networks [Member] Accounts Receivable [Member]	Dec. 31, 2013 Nokia Siemens Networks [Member] Accounts Receivable [Member]	Mar. 31, 2014 Arbor Networks [Member]	Mar. 31, 2014 Arbor Networks [Member] Accounts Receivable [Member]	Mar. 31, 2014 NEC [Member]	Mar. 31, 2013 NEC [Member]	Mar. 31, 2014 NEC [Member] Accounts Receivable [Member]
Concentration Risk [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	18.00%	17.40%	22.40%	20.70%	14.20%	13.10%	13.70%	14.50%	13.70%