Reclassifications - Schedule of Marketing and General and Administrative Expenses Reclassified (Details) (Marketing Expenses Reclassified to Costs of Revenues [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013
Marketing Expenses Reclassified to Costs of Revenues [Member]
Costs of free trials allocated to marketing reclassified to cost of revenues	$ 7.9	$ 25.1