Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Jan. 31, 2020	Apr. 30, 2019	Feb. 01, 2019
Assets
Operating lease right-of-use assets	$ 2,300	$ 3,000	$ 2,710
Liabilities
Total operating lease liabilities	2,300	3,000	2,710
Current liabilities	1,339
Non-current liabilities	961
Total Operating lease liabilities	$ 2,300	$ 3,000	$ 2,710
Weighted average remaining lease term (years)
Operating leases	1 year 9 months 5 days
Weighted average discount rate:
Operating leases	9.27%