Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenue:
Product	$ 52,357	$ 46,162	$ 95,334	$ 86,424
Service	39,740	38,383	78,568	74,482
Total revenue	92,097	84,545	173,902	160,906
Cost of revenue:
Product	11,810	10,330	21,583	20,400
Service	7,894	6,611	15,043	13,404
Total cost of revenue	19,704	16,941	36,626	33,804
Gross profit	72,393	67,604	137,276	127,102
Operating expenses:
Research and development	16,638	15,201	32,603	29,278
Sales and marketing	31,559	26,743	63,759	56,892
General and administrative	7,457	6,975	14,438	13,532
Amortization of acquired intangible assets	857	645	1,711	1,231
Restructuring charges	0	1,153	0	1,066
Total operating expenses	56,511	50,717	112,511	101,999
Income from operations	15,882	16,887	24,765	25,103
Interest and other (expense) income, net:
Interest income	57	192	144	308
Interest expense	(187)	(401)	(377)	(792)
Other income expense, net	71	93	101	12
Total interest and other expense income, net	(59)	(116)	(132)	(472)
Income before income tax expense	15,823	16,771	24,633	24,631
Income tax expense	5,940	6,861	9,497	9,713
Net income	$ 9,883	$ 9,910	$ 15,136	$ 14,918
Basic net income per share (in dollars per share)	$ 0.24	$ 0.24	$ 0.37	$ 0.36
Diluted net income per share (in dollars per share)	$ 0.24	$ 0.23	$ 0.36	$ 0.35
Weighted average common shares outstanding used in computing:
Net income per share - basic (in shares)	41,392	41,695	41,398	41,718
Net income per share - diluted (in shares)	41,950	42,344	42,004	42,400