CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss	$ (37,588)	$ (20,647)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	5,269	3,591
Depreciation and amortization	816	84
Noncash interest expense	126	14
Net amortization of premiums and discounts on short-term investments	409	(730)
Changes in operating assets and liabilities:
Research and development incentives receivable	(1,438)	(1,241)
Prepaid expenses and other current assets	(1,932)	(2,128)
Operating lease, right-of-use-asset	238	250
Finance lease, right-of-use-asset	1,188	60
Long term prepaid rent		(12,433)
Accounts payable	(1,198)	(900)
Accrued expenses and other current liabilities	2,023	669
Operating lease liabilities	(182)	(144)
Net cash used in operating activities	(32,269)	(33,555)
Cash flows from investing activities:
Purchases of property, plant and equipment	(1,007)	(1,146)
Purchase of short-term investments	(196,535)	(30,628)
Proceed from sales and maturities of short-term investments	103,618	83,909
Net cash provided by (used in) investing activities	(93,924)	52,135
Cash flows from financing activities:
Proceeds from long-term debt, net of debt issuance costs	(100)	9,645
Proceeds from issuance of common stock in follow-on public offering, net of issuance costs	74,883
Proceeds from issuance of prefunded warrants to purchase common stock, net of issuance costs	32,900
Principal payment of finance lease obligation	(42)
Exercise of stock options	1,838	123
Net cash provided by financing activities	109,479	9,768
Effect of exchange rate changes on cash, cash equivalents and restricted cash	540	(304)
Net increase in cash, cash equivalents and restricted cash	(16,174)	28,044
Cash, cash equivalents and restricted cash at beginning of period	61,136	26,890
Cash, cash equivalents and restricted cash at end of period	44,962	54,934
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	445
Supplemental disclosure of non-cash investing and financing activities:
Net unrealized gain (loss) on short-term investments	244	(25)
Purchases of property and equipment included in accounts payable	79	1,825
Lease assets obtained in exchange for new financing lease liabilities		7,165
Lease assets obtained in exchange for new operating lease liabilities	$ 1,580	$ 5,152