Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Revenue:
Product	$ 68,561	$ 52,676	$ 163,895	$ 139,100
Service	41,867	38,891	120,435	113,373
Total revenue	110,428	91,567	284,330	252,473
Cost of revenue:
Product	14,534	12,182	36,117	32,582
Service	9,068	6,982	24,111	20,386
Total cost of revenue	23,602	19,164	60,228	52,968
Gross profit	86,826	72,403	224,102	199,505
Operating expenses:
Research and development	18,348	15,352	50,951	44,630
Sales and marketing	32,425	30,105	96,184	86,997
General and administrative	7,929	8,539	22,367	22,071
Amortization of acquired intangible assets	860	846	2,571	2,077
Restructuring charges	0	(1)	0	1,065
Total operating expenses	59,562	54,841	172,073	156,840
Income from operations	27,264	17,562	52,029	42,665
Interest and other income (expense), net:
Interest income	66	115	210	423
Interest expense	(198)	(293)	(575)	(1,085)
Other income, net	176	74	277	86
Total interest and other income (expense), net	44	(104)	(88)	(576)
Income before income tax expense	27,308	17,458	51,941	42,089
Income tax expense	10,014	6,320	19,511	16,033
Net income	$ 17,294	$ 11,138	$ 32,430	$ 26,056
Basic net income per share (in dollars per share)	$ 0.42	$ 0.27	$ 0.78	$ 0.62
Diluted net income per share (in dollars per share)	$ 0.41	$ 0.26	$ 0.77	$ 0.62
Weighted average common shares outstanding used in computing:
Net income per share - basic (in shares)	41,425	41,709	41,417	41,715
Net income per share - diluted (in shares)	41,884	42,298	41,969	42,364