Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenue:
Product	$ 46,162	$ 38,080	$ 86,424	$ 67,611
Service	38,383	34,544	74,482	68,309
Total revenue	84,545	72,624	160,906	135,920
Cost of revenue:
Product	10,330	9,061	20,400	16,708
Service	6,611	6,516	13,404	12,765
Total cost of revenue	16,941	15,577	33,804	29,473
Gross profit	67,604	57,047	127,102	106,447
Operating expenses:
Research and development	15,201	11,160	29,278	22,480
Sales and marketing	26,743	26,854	56,892	53,626
General and administrative	6,975	7,037	13,532	13,571
Amortization of acquired intangible assets	645	494	1,231	976
Restructuring charges	1,153	0	1,066	0
Total operating expenses	50,717	45,545	101,999	90,653
Income from operations	16,887	11,502	25,103	15,794
Interest and other expense, net:
Interest income	192	101	308	200
Interest expense	(401)	(477)	(792)	(977)
Other income (expense), net	93	(459)	12	(457)
Total interest and other expense, net	(116)	(835)	(472)	(1,234)
Income before income tax expense	16,771	10,667	24,631	14,560
Income tax expense	6,861	3,616	9,713	5,110
Net income	$ 9,910	$ 7,051	$ 14,918	$ 9,450
Basic net income per share	$ 0.24	$ 0.17	$ 0.36	$ 0.22
Diluted net income per share	$ 0.23	$ 0.17	$ 0.35	$ 0.22
Weighted average common shares outstanding used in computing:
Net income per share - basic	41,695	42,258	41,718	42,433
Net income per share - diluted	42,344	42,720	42,400	43,061