Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Allowance for estimated product returns	$ 1.1	$ 2.2
Weighted Average [Member] | Online Service Agreements [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Revenue recognition, period for recognition	12 months
Minimum [Member] | License Update [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Revenue recognition, period for recognition	12 months
Maximum [Member] | License Update [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Revenue recognition, period for recognition	24 months