Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended									12 Months Ended
	Apr. 30, 2016		Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 50,709	[1]	$ 50,255	$ 49,926	$ 48,876	$ 48,317	$ 49,562	$ 47,325	$ 45,977	$ 199,766	$ 191,181	$ 168,145
Cost of revenue	19,253		18,920	19,146	19,548	18,148	17,988	17,414	16,356	76,867	69,906	52,905
Gross Profit	31,456		31,335	30,780	29,328	30,169	31,574	29,911	29,621	122,899	121,275	115,240
Sales and marketing	18,027		16,113	16,502	19,166	20,427	18,020	18,931	20,995	69,808	78,373	86,482
Research and development	10,391		10,199	10,354	10,533	9,880	8,779	9,306	9,730	41,477	37,695	37,585
General and administrative	7,577		6,940	7,643	8,238	7,582	6,932	8,100	7,893	30,398	30,507	26,370
Acquisition-related and other	157		332	224	702	815	413	2,326	492	1,415	4,046	16,184
Restructuring charges	1,575		0	0	0	0	0	0	0	1,575	0	0
Amortization of acquired intangible assets	309		309	310	309	309	309	310	309	1,237	1,237	1,135
Operating Expenses	38,036		33,893	35,033	38,948	39,013	34,453	38,973	39,419	145,910	151,858	167,756
Operating loss	(6,580)		(2,558)	(4,253)	(9,620)	(8,844)	(2,879)	(9,062)	(9,798)	(23,011)	(30,583)	(52,516)
Total other expense, net	(384)		(719)	(475)	(712)	(521)	(920)	(588)	(498)	(2,290)	(2,527)	(830)
Net loss before income taxes	(6,964)		(3,277)	(4,728)	(10,332)	(9,365)	(3,799)	(9,650)	(10,296)	(25,301)	(33,110)	(53,346)
Income tax expense (benefit)	165		(163)	124	(88)	(540)	324	258	12	38	54	(500)
Net loss from continuing operations	(7,129)		(3,114)	(4,852)	(10,244)	(8,825)	(4,123)	(9,908)	(10,308)	(25,339)	(33,164)	(52,846)
Loss from discontinued operations, net of tax	0		0	0	0	0	0	0	(1,257)	0	(1,257)	(10,320)
Net loss applicable to common stockholders	$ (7,129)		$ (3,114)	$ (4,852)	$ (10,244)	$ (8,825)	$ (4,123)	$ (9,908)	$ (11,565)	$ (25,339)	$ (34,421)	$ (63,166)
Continuing operations	$ (0.09)		$ (0.04)	$ (0.06)	$ (0.13)	$ (0.11)	$ (0.05)	$ (0.13)	$ (0.13)	$ (0.31)	$ (0.42)	$ (0.70)
Discontinued operations	0.00		0.00	0.00	0.00	0.00	0.00	0.00	(0.02)	0.00	(0.02)	(0.14)
Basic loss per share:	$ (0.09)		$ (0.04)	$ (0.06)	$ (0.13)	$ (0.11)	$ (0.05)	$ (0.13)	$ (0.15)	$ (0.31)	$ (0.44)	$ (0.84)

[1] During the fourth quarter of fiscal 2016, the Company recorded out of period adjustments related to errors in the timing of recognition of revenue, for which all required criteria had been satisfied in prior periods. The cumulative effect of out of period adjustments for the fourth quarter of fiscal 2016 was a $0.9 million increase in revenue. The Company has determined that these adjustments were not material to any prior annual or interim periods, and the resulting correction is not material to its annual results for fiscal 2016 or to the trend in earnings.