Leases - Summary of Components of Lease Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Lease cost
Operating lease cost	$ 63	$ 0	$ 127	$ 0
Finance lease cost	0	0	0	0
Amortization of right-of-use assets	0	0	0	0
Interest on lease liabilities	0	0	0	0
Variable lease costs	0	0	0	0
Total lease cost	63	0	127	0
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	66	0	131	0
Operating cash flows from finance leases	0	0	0	0
Financing cash flows from finance leases	0	0	0	0
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	0	0	650	0
Finance leases	$ 0	$ 0	$ 5	$ 0