Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (198,537)	$ (95,002)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation	13,763	8,243
Depreciation	298	167
Amortization of debt discount and issuance costs	1,378	390
Foreign currency translation adjustment	203	(231)
Other	596	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(7,235)	(2,058)
Deferred tax assets	0	208
Income tax receivable	233	(502)
Other assets	(146)	(2,098)
Accounts payable	893	(1,238)
Interest payable	147	0
Accrued expenses	18,079	8,838
Due to RSL, RSI and RSG	(1,894)	653
Deferred rent	724	259
Deferred interest payable	518	105
Net cash used in operating activities	(170,980)	(82,266)
Cash flows from investing activities:
Purchase of property and equipment	(718)	(375)
Net cash used in investing activities	(718)	(375)
Cash flows from financing activities:
Cash proceeds from debt financings, net of financing costs paid	54,000	28,803
Cash proceeds from stock option exercises	771	16
Cash paid to NovaQuest for annual debt administration fee	(300)	0
Net cash provided by financing activities	246,677	30,676
Net change in cash, cash equivalents and restricted cash	74,979	(51,965)
Cash, cash equivalents and restricted cash, beginning of period	108,624	180,838
Cash, cash equivalents and restricted cash, end of period	183,603	128,873
Non-cash financing activities:
Stock options exercised receivables, included in prepaid expenses and other current assets	(22)	0
Deferred financing costs included in accrued expenses	26	137
Offering costs included in accrued expenses	18	0
Warrant issued to Hercules	0	481
Public Offering
Cash flows from financing activities:
Cash proceeds from issuance of common shares	74,391	0
Private Placement | Cowen and Company, LLC
Cash flows from financing activities:
Cash proceeds from issuance of common shares	57,315	0
Private Placement | Roivant Sciences, Ltd.
Cash flows from financing activities:
Cash proceeds from issuance of common shares	22,500	0
Private Placement | NovaQuest
Cash flows from financing activities:
Cash proceeds from issuance of common shares	$ 38,000	$ 1,857