Significant Accounting Policies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Net Revenues,licensing agreement with subscription bundle	1 year
Allowance for estimated product returns		$ 2.0	$ 2.6
Online Service Agreements [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Revenue recognition, period for recognition, average	12 months
Licence Update [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Revenue recognition, period for recognition, lower end of range	12 months
Revenue recognition, period for recognition, higher end of range	24 months