Summary Of Significant Accounting Policies (Share-Based Compensation Cost) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized compensation cost (stock options)	$ 15,200,000		$ 15,200,000
Weighted average vesting period, years			1 year 11 months
Share-based compensation cost	8,773,000	6,531,000	17,469,000	12,679,000
Selling And Marketing [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation cost	3,749,000	2,570,000	6,866,000	5,024,000
General And Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation cost	3,462,000	2,685,000	7,297,000	5,223,000
Research And Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation cost	1,562,000	1,276,000	3,306,000	2,432,000
Restricted Stock and Restricted Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized compensation cost	$ 56,300,000		$ 56,300,000