Leases - Supplemental Cash Flow Information and Non-Cash Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Operating cash flow information:
Cash payments included in the measurement of lease liabilities	$ 1,500	$ 1,270	$ 0
Non-cash activity:
Right-of-use assets obtained in exchange for lease obligations	$ 4,520	$ 815	$ 0