Leases (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Jun. 30, 2020	Jul. 31, 2020	Apr. 30, 2021	Apr. 30, 2020	Apr. 01, 2021	Jun. 01, 2020	May 01, 2020
Lessee, Lease, Description [Line Items]
Operating leases, rent expense			$ 1,247	$ 955
Renewal term			6 months
Operating lease right-of-use assets, net			$ 8,521	2,798			$ 2,798
Operating lease, liability					$ 3,300
Operating lease incremental rent expense			43
Gain on termination of operating lease			$ 75	0
Weighted average remaining lease term			7 years 9 months 10 days
Weighted average discount rate			5.78%
Corporate Headquarters
Lessee, Lease, Description [Line Items]
Operating leases, rent expense			$ 91	94
Rockville, MD
Lessee, Lease, Description [Line Items]
Operating leases, rent expense			1,113	604
Operating lease right-of-use assets, net		$ 118				$ 3,800
Operating lease, liability		125
Operating lease incremental rent expense		$ 8
Rockville, MD New Location
Lessee, Lease, Description [Line Items]
Operating leases, rent expense			$ 43	$ 257
Operating lease right-of-use assets, net	$ 850
Operating lease, liability	926
Gain on termination of operating lease	$ 76