Organization, Use of Estimates and Basis of Presentation - Narrative (Details) $ in Thousands		3 Months Ended		6 Months Ended
	Oct. 15, 2013	Oct. 31, 2016 USD ($)	Oct. 31, 2015 USD ($)	Oct. 31, 2016 USD ($) subsidiary	Oct. 31, 2015 USD ($)	Apr. 30, 2016 USD ($)	Apr. 30, 2015 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating subsidiaries | subsidiary				2
Net loss attributable to common stockholders		$ (504)	$ (2,548)	$ (3,051)	$ (5,461)
Positive working capital		2,100		2,100
Cash and cash equivalents		4,328	4,157	4,328	4,157	$ 2,585	$ 9,357
Reverse stock split conversion ratio	0.0833
Net cash used in operating activities		(116)		2,555	5,127
Unrecognized tax benefits		185		185		$ 165
(Benefit from) Provision for income taxes		$ (5)	$ 41	$ 9	$ 47