Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands		6 Months Ended
		Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net loss		$ (138,472)	$ (127,904)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation		14,383	8,969
Depreciation and amortization	[1]	726	191
Amortization of debt discount and issuance costs		1,095	936
Other items		(369)	565
Changes in operating assets and liabilities:
Prepaid expenses and other current assets		225	(3,240)
Income tax receivable		507	233
Other assets		(799)	(96)
Accounts payable		(5,200)	3,781
Interest payable		(772)	18
Accrued expenses		(9,304)	8,176
Operating lease liabilities		(368)
Due to RSL, RSI and RSG		150	(1,382)
Deferred rent		0	567
Deferred interest payable		3,050	305
Net cash used in operating activities		(135,148)	(108,881)
Cash flows from investing activities:
Purchases of marketable securities		(27,160)	0
Purchases of property and equipment		(532)	(390)
Net cash used in investing activities		(27,692)	(390)
Cash flows from financing activities:
Proceeds from stock option exercises		314	466
Net cash provided by financing activities		137,388	154,964
Net change in cash, cash equivalents and restricted cash		(25,452)	45,693
Cash, cash equivalents and restricted cash, beginning of period		157,199	108,624
Cash, cash equivalents and restricted cash, end of period		131,747	154,317
Non-cash financing activities:
Unpaid offering costs included in accounts payable and accrued expenses		70	292
Stock options exercised receivables, included in prepaid expenses and other current assets		0	(70)
Public Offering
Cash flows from financing activities:
Cash proceeds from issuance of common shares		134,528	74,683
Private Placement | Cowen and Company, LLC
Cash flows from financing activities:
Cash proceeds from issuance of common shares		2,546	57,315
Private Placement | Roivant Sciences, Ltd.
Cash flows from financing activities:
Cash proceeds from issuance of common shares		$ 0	$ 22,500

[1] Includes amortization of operating lease right-of-use asset.