Discontinued Operations - Additional Information (Details) (USD $)
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]    
Gain from sale of discontinued operations, net of taxes $ 0 $ 0
Additional cash consideration payable to Polycom as a result of EWS disposition | Maximum    
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]    
Additional cash consideration payable over the next two years subject to certain conditions, including meeting certain agreed-upon EBITDA-based milestones $ 25,000,000