Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2016	Jan. 31, 2015
Income Statement [Abstract]
Revenue	$ 50,255	$ 49,562	$ 149,057	$ 142,864
Cost of revenue	18,920	17,988	57,614	51,758
Gross profit	31,335	31,574	91,443	91,106
Operating expenses:
Sales and marketing	16,113	18,020	51,781	57,946
Research and development	10,199	8,779	31,086	27,815
General and administrative	6,940	6,932	22,821	22,925
Acquisition-related and other	332	413	1,258	3,231
Amortization of acquired intangible assets	309	309	928	928
Total operating expenses	33,893	34,453	107,874	112,845
Operating loss	(2,558)	(2,879)	(16,431)	(21,739)
Other income (expense), net:
Interest income	124	27	275	43
Interest expense	(596)	(536)	(1,628)	(1,018)
Other expense	(247)	(411)	(553)	(1,031)
Total other expense, net	(719)	(920)	(1,906)	(2,006)
Loss from continuing operations before income taxes	(3,277)	(3,799)	(18,337)	(23,745)
Income tax expense (benefit)	(163)	324	(127)	594
Net loss from continuing operations	(3,114)	(4,123)	(18,210)	(24,339)
Loss from discontinued operations, net of tax	0	0	0	(1,257)
Net loss applicable to common stockholders	$ (3,114)	$ (4,123)	$ (18,210)	$ (25,596)
Net loss per share applicable to common stockholders:
Continuing operations	$ (0.04)	$ (0.05)	$ (0.23)	$ (0.31)
Discontinued operations	0.00	0.00	0.00	(0.02)
Basic and diluted loss per share:	$ (0.04)	$ (0.05)	$ (0.23)	$ (0.33)
Basic and diluted weighted average number of shares outstanding	81,096	78,898	80,649	78,315