Allowance for Doubtful Accounts Receivable and Sales Returns (Additional Information) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Accounts Receivable
Concentration Risk [Line Items]
Number of major customers	1	1
Accounts Receivable | Company A
Concentration Risk [Line Items]
Percentage by major customer			13.00%
Accounts Receivable | Company B
Concentration Risk [Line Items]
Percentage by major customer			12.00%
Revenue by Segment
Concentration Risk [Line Items]
Percentage by major customer	12.00%	11.00%	14.00%
RealPlayer Group
Concentration Risk [Line Items]
Significant customer revenue	$ 6.0	$ 6.4	$ 21.1
Mobile Entertainment
Concentration Risk [Line Items]
Significant customer revenue	$ 6.8		$ 17.3
Mobile Entertainment | Revenue by Segment
Concentration Risk [Line Items]
Percentage by major customer	14.00%		11.00%