Consolidated Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended										12 Months Ended
	Mar. 31, 2016		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015		Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Quarterly Financial Data Details
Service revenue	$ 52,174		$ 48,948	$ 46,951	$ 44,168	$ 40,009		$ 37,802	$ 36,121	$ 34,276	$ 192,241	$ 148,208	$ 116,607
Product revenue	5,160		4,220	3,991	3,724	3,521		3,570	3,477	3,637	17,095	14,205	11,990
Total revenue	57,334		53,168	50,942	47,892	43,530		41,372	39,598	37,913	209,336	162,413	128,597
Operating expenses:
Cost of service revenue	9,720		9,713	9,186	8,459	7,655		7,544	7,505	6,997	37,078	29,701	22,445
Cost of product revenue	6,103		5,087	4,596	4,382	4,173		3,959	3,762	3,969	20,168	15,863	15,170
Research and development	6,110		6,404	6,446	5,080	4,348		3,868	3,496	3,406	24,040	15,118	11,633
Sales and marketing	31,240		27,585	26,370	23,824	21,508		20,559	19,440	19,160	109,379	80,667	60,906
General and administrative	7,132		6,888	5,657	6,068	5,794		4,617	3,893	3,878	25,745	18,182	15,368
Gain on patent sale	0		0	0	0	0		0	(1,000)	0	0	(1,000)	0
Total operating expenses	60,305		55,677	52,615	47,813	43,478		40,547	37,096	37,410	216,410	158,531	125,522
Income (loss) from operations	(2,971)		(2,509)	(1,673)	79	52		825	2,502	503	(7,074)	3,882	3,075
Other income, net	397		272	204	234	210		246	200	177
Income (loss) from continuing operations before provision (benefit) for income taxes	(2,574)		(2,237)	(1,469)	313	262		1,071	2,702	680	(5,967)	4,715	3,817
Provision (benefit) for income taxes (1)	(1,498)	[1]	(557)	423	785	79	[1]	627	1,411	672	(847)	2,789	2,219
Net income (loss)	$ (1,076)		$ (1,680)	$ (1,892)	$ (472)	$ 183		$ 444	$ 1,291	$ 8	$ (5,120)	$ 1,926	$ 2,514
Net income (loss) per share:
Basic	$ (0.01)		$ (0.02)	$ (0.02)	$ (0.01)	$ 0.00		$ 0.01	$ 0.01	$ 0.00	$ (0.06)	$ 0.02	$ 0.03
Diluted	$ (0.01)		$ (0.02)	$ (0.02)	$ (0.01)	$ 0.00		$ 0.01	$ 0.01	$ 0.00	$ (0.06)	$ 0.02	$ 0.03
Shares used in per share calculations:
Basic	88,888		88,289	88,557	88,233	88,950		89,594	89,073	88,592	88,477	89,071	78,310
Diluted	88,888		88,289	88,557	88,233	91,266		91,974	91,615	91,445	88,477	91,652	81,658

[1] Comparability affected by the decrease in fiscal 2016 and 2015 in the valuation allowance related to the deferred tax asset which resulted in a decrease in the provision for income taxes of $1.1 million and $1.5 million, in the fourth quarter of fiscal 2016 and 2015, respectively.