Stock-Based Compensation (Schedule Of Stock-Based Compensation Expense) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 30, 2012	Apr. 30, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	$ 8,146	$ 11,077
Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	699	1,893
Restricted/Deferred Stock Awards [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	7,447	9,184
Product Costs [Member] | Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	23	97
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	113	172
Service Costs [Member] | Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	76	166
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	765	645
Research and Development [Member] | Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	91	240
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	551	775
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	509	1,390
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	$ 6,018	$ 7,592