Property and Equipment - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended
	Jul. 31, 2018	Nov. 30, 2014	Jul. 31, 2019	Jul. 31, 2018	Apr. 30, 2019
Property, Plant and Equipment [Line Items]
Depreciation			$ 145	$ 111
Assets under finance lease			366		$ 366
Finance leases monthly payments	$ 11
Finance Leased Assets
Property, Plant and Equipment [Line Items]
Depreciation			37	7
Equipment Leased to Other Party
Property, Plant and Equipment [Line Items]
Finance lease, liability	$ 283	$ 149		$ 283
Finance leases monthly payments		$ 3
Future minimum lease payments remaining			$ 9
Discount rate			5.00%
Minimum
Property, Plant and Equipment [Line Items]
Useful lives			3 years
Maximum
Property, Plant and Equipment [Line Items]
Useful lives			7 years