Stock-Based Compensation (Schedule Of Stock-Based Compensation Expense) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2011	Oct. 31, 2010
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	$ 8,660	$ 15,834	$ 28,081	$ 47,587
Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	474	6,997	3,278	19,827
Restricted/Deferred Stock Awards [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	8,186	8,837	24,803	27,760
Product Costs [Member] | Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	6	271	133	698
Product Costs [Member] | Restricted/Deferred Stock Awards [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	242	234	564	694
Service Costs [Member] | Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	41	742	268	2,265
Service Costs [Member] | Restricted/Deferred Stock Awards [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	582	550	1,817	1,864
Selling, General And Administrative [Member] | Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	376	4,743	2,443	12,960
Selling, General And Administrative [Member] | Restricted/Deferred Stock Awards [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	6,689	7,389	20,286	22,647
Research And Development [Member] | Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	51	1,241	434	3,904
Research And Development [Member] | Restricted/Deferred Stock Awards [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	$ 673	$ 664	$ 2,136	$ 2,555