Income Taxes - Unrecognized Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning of period balance	$ 3,177	$ 0	$ 0
Gross increases — prior period tax positions	0	2,067	0
Gross decreases — prior period tax positions	(128)	0	0
Gross increases — current period tax positions	1,355	1,110	0
End of period balance	$ 4,404	$ 3,177	$ 0