Schedule of Allocation of Share Based Compensation Costs for Deferred Share Units (Details)	6 Months Ended
	Oct. 31, 2017 USD ($)
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 1	$ 0
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 2	0
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 3	0
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 4	0
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 5	0
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 6	0
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 7	0
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 8	0
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 9	38,552
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 10	32,508
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 11	233,155
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 12	231,415
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 13	38,552
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 14	32,508
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 15	233,155
Common Stock Schedule Of Allocation Of Share Based Compensation Costs For Deferred Share Units 16	$ 231,415