Provision for Income Taxes - Components of Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2016	Apr. 30, 2015
Federal Income Tax Expense (Benefit), Continuing Operations [Abstract]
Provision for Income Taxes, Current, Federal	$ 0	$ 0
Provision for Income Taxes, Deferred, Federal	(3,322)	(3,912)
Provision for Income Taxes, Change in valuation allowance, Federal	3,322	3,912
Provision for Income Taxes, Total, Federal	0	0
State and Local Income Tax Expense (Benefit), Continuing Operations [Abstract]
Provision for Income Taxes, Current, State	0	3
Provision for Income Taxes, Deferred, State	(537)	(287)
Provision for Income Taxes, Change in valuation allowance, State	537	287
Provision for Income Taxes, Total, State	0	3
Foreign Income Tax Expense (Benefit), Continuing Operations [Abstract]
Provision for Income Taxes, Current, Foreign	92	124
Provision for Income Taxes, Deferred, Foreign	11	8
Provision for Income Taxes, Change in valuation allowance, Foreign	(11)	(8)
Provision for Income Taxes, Total, Foreign	92	124
Provision for Income Taxes, Current, Total	92	127
Provision for Income Taxes, Deferred, Total	(3,848)	(4,191)
Provision for Income Taxes, Change in valuation allowance, Total	3,848	4,191
Provision for Income Taxes, Total	$ 92	$ 127