Derivative Instruments And Hedging Activities (Effect Of Foreign Exchange Forward Contracts On OCI And Results Of Operations) (Details) (USD $) In Thousands	3 Months Ended				6 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	$ (480)	[1]	$ 433	[1]	$ (296)	[1]	$ (129)	[1]
Gain (Loss) Reclassified from Accumulated OCI into Income	56	[2]	(171)	[2]	231	[2]	(433)	[2]
Gain (Loss) Recognized in Income (Amount Excluded from Effectiveness Testing)	52	[3]	18	[3]	112	[3]	9	[3]
Forward Contracts [Member] | Research And Development [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) Recognized in OCI on Derivative	(480)	[1]	433	[1]	(296)	[1]	(129)	[1]
(Loss) Reclassified from Accumulated OCI into Income	(17)	[2]	(14)	[2]	(3)	[2]	(7)	[2]
Gain Recognized in Income (Amount Excluded from Effectiveness Testing)	21	[3]	24	[3]	77	[3]	8	[3]
Forward Contracts [Member] | Sales And Marketing [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain Reclassified from Accumulated OCI into Income	73	[2]			234	[2]
(Loss) Reclassified from Accumulated OCI into Income			(157)	[2]			(426)	[2]
Gain Recognized in Income (Amount Excluded from Effectiveness Testing)	31	[3]			35	[3]	1	[3]
(Loss) Recognized in Income (Amount Excluded from Effectiveness Testing)			$ (6)	[3]

[1] The amount represents the change in fair value of derivative contracts due to changes in spot rates.

[2] The amount represents reclassification from other comprehensive income to earnings that occurs when the hedged item affects earnings.

[3] The amount represents the change in fair value of derivative contracts due to changes in the difference between the spot price and forward price that is excluded from the assessment of hedge effectiveness and therefore recognized in earnings. No gains or losses were reclassified as a result of discontinuance of cash flow hedges.