Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Oct. 31, 2019	Apr. 30, 2019	Feb. 01, 2019
Assets
Operating lease right-of-use assets	$ 2,455	$ 3,000	$ 2,710
Liabilities
Total operating lease liabilities	2,455	3,000	2,710
Current liabilities	367
Non-current liabilities	2,088
Total Operating lease liabilities	$ 2,455	$ 3,000	$ 2,710
Weighted average remaining lease term (years)
Operating leases	1 year 11 months 1 day
Weighted average discount rate:
Operating leases	10.02%