LEASE - Lease expense (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Finance lease cost
Amortization of leased asset			$ 2,123,901	$ 40,730
Total lease expenses	$ 1,339,984	$ 126,438	2,482,258	209,176
Selling, general and administrative
Operating lease cost
Lease expenses	99,684	126,438	205,880	209,176
Cost of revenue
Finance lease cost
Amortization of leased asset	489,829	0	766,348	0
General and administrative
Finance lease cost
Amortization of leased asset	539,418	0	1,072,800	0
Interest expenses on finance leases
Finance lease cost
Interest on lease liabilities	$ 211,053	$ 0	$ 437,230	$ 0