Schedule of Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Mar. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Cost	$ 98,769	$ 81,912
Accumulated Amortization	(33,336)	(27,227)
Net	65,433	54,685
Developed Technology
Finite-Lived Intangible Assets [Line Items]
Cost	33,677	24,919
Accumulated Amortization	(21,318)	(17,943)
Net	12,359	6,976
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Cost	38,743	32,754
Accumulated Amortization	(10,351)	(8,492)
Net	28,392	24,262
Distributor Relationships
Finite-Lived Intangible Assets [Line Items]
Cost	1,931
Accumulated Amortization	(142)
Net	1,789
Indefinite Lived Trade Name
Finite-Lived Intangible Assets [Line Items]
Cost	18,600	18,600
Accumulated Amortization	0	0
Net	18,600	18,600
Core Technology
Finite-Lived Intangible Assets [Line Items]
Cost	4,744	4,760
Accumulated Amortization	(812)	(306)
Net	3,932	4,454
Net Beneficial Leases
Finite-Lived Intangible Assets [Line Items]
Cost	336	336
Accumulated Amortization	(336)	(334)
Net	0	2
Non-Compete Agreements
Finite-Lived Intangible Assets [Line Items]
Cost	341	343
Accumulated Amortization	(142)	(57)
Net	199	286
Other
Finite-Lived Intangible Assets [Line Items]
Cost	397	200
Accumulated Amortization	(235)	(95)
Net	$ 162	$ 105