Income Taxes - State Net Operating Loss Carryforwards and Valuation Allowances (Details) - USD ($) $ in Thousands	Apr. 30, 2019	Apr. 30, 2018
Operating loss carryforwards
Net operating loss carry forwards	$ 2,300	$ 4,000
Valuation allowance
Valuation allowance	1,112	448
State
Operating loss carryforwards
Net operating loss carry forwards	$ 23,100	$ 20,400