Organization, Use of Estimates and Basis of Presentation - Narrative (Details)		3 Months Ended		9 Months Ended
	Oct. 15, 2013	Jan. 31, 2017 USD ($)	Jan. 31, 2016 USD ($)	Jan. 31, 2017 USD ($) subsidiary	Jan. 31, 2016 USD ($)	Apr. 30, 2016 USD ($)	Apr. 30, 2015 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating subsidiaries | subsidiary				2
Net loss		$ 1,408,904	$ 2,412,381	$ 4,459,773	$ 7,872,115
Net cash used in operating activities		684,000		3,238,000	5,853,000
Positive working capital		8,000		8,000
Cash and cash equivalents		3,488,000	3,293,000	3,488,000	3,293,000	$ 2,585,000	$ 9,357,000
Reduction in net loss				3,400,000
Reduction in use of cash in operations				2,600,000
Reverse stock split conversion ratio	0.0833
Unrecognized tax benefits		185,000		185,000		$ 165,000
Provision for income taxes		$ 0	$ 31,000	$ 7,000	$ 76,000