Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
Income Statement [Abstract]
Revenue	$ 201,235	$ 199,766	$ 191,181
Cost of revenue	76,403	76,867	69,906
Gross profit	124,832	122,899	121,275
Operating expenses:
Sales and marketing	65,248	69,808	78,373
Research and development	40,087	41,477	37,695
General and administrative	31,952	30,398	30,507
Restructuring charges	2,202	1,575	0
Sales tax refund	(3,341)	0	0
Acquisition-related and other	576	1,415	4,046
Amortization of acquired intangible assets	1,237	1,237	1,237
Total operating expenses	137,961	145,910	151,858
Operating loss	(13,129)	(23,011)	(30,583)
Other income (expense), net:
Interest income	629	412	95
Interest expense	(1,855)	(2,180)	(1,451)
Other expense	(1,033)	(522)	(1,171)
Total other expense, net	(2,259)	(2,290)	(2,527)
Loss from continuing operations before income taxes	(15,388)	(25,301)	(33,110)
Income tax expense	553	38	54
Net loss from continuing operations	(15,941)	(25,339)	(33,164)
Loss from discontinued operations, net of tax	0	0	(1,257)
Net loss applicable to common stockholders	$ (15,941)	$ (25,339)	$ (34,421)
Net loss per share applicable to common stockholders:
Continuing operations	$ (0.19)	$ (0.31)	$ (0.42)
Discontinued operations	0.00	0.00	(0.02)
Basic and diluted loss per share	$ (0.19)	$ (0.31)	$ (0.44)
Basic and diluted weighted average number of shares outstanding	83,051	80,859	78,645