Leases - Additional Information (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Oct. 31, 2019 USD ($)	Oct. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Cash paid included in measurement of operating lease liabilities		$ 500
Amortization of lease cost		10
Lease income	$ 54	$ 111
Minimum
Lessee, Lease, Description [Line Items]
Lease term	3 years	3 years
Maximum
Lessee, Lease, Description [Line Items]
Lease term	5 years	5 years