Income Taxes (Schedule of Defered Income Tax Assets and Liabilities) (Details) - USD ($)	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
Deferred tax assets:
Net operating loss	$ 7,163,547	$ 8,626,748
Allowance for doubtful accounts (recovery)	105,122	(20,029)
Intangible assets	(6,573)	201,942
Deferred rent	20,574	16,911
Stock-based compensation	687,067	820,257
Contributions carryforward	60	93
Total deferred tax assets	7,969,797	9,645,922
Deferred tax liabilities:
Property and equipment	(132,042)	(174,260)
Total deferred tax liabilities	(132,042)	(174,260)
Deferred tax assets, net	7,837,755	9,471,662
Valuation allowance:
Valuation allowance	(7,837,755)	(9,471,662)	$ (9,068,774)
Net deferred tax asset