Organization, Use of Estimates and Basis of Presentation - Narrative (Details) $ in Thousands	3 Months Ended
	Jul. 31, 2018 USD ($) subsidiary	Jul. 31, 2017 USD ($)	Apr. 30, 2018 USD ($)	Oct. 30, 2017 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating subsidiaries | subsidiary	2
Restricted cash	$ 150		$ 150
Net income (loss)	482	$ (674)
Accumulated deficit	70,344		70,826
Net cash used in operating activities	(336)	1,948
Positive working capital	1,900
Cash and cash equivalents	1,016		856
Credit facility				$ 1,500
Unrecognized tax benefits	151		$ 151
Provision for income taxes	$ 0	$ 4