Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands		3 Months Ended
		Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net loss		$ (32,860)	$ (67,904)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation		7,812	6,452
Depreciation and amortization	[1]	551	356
Amortization of debt discount and issuance costs		0	555
Foreign currency transaction gain		(3,569)	(705)
Other		94	(8)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets		(1,101)	1,501
Income tax receivable		0	193
Other assets		0	237
Accounts payable		(9,946)	(1,015)
Interest payable		0	(319)
Interest payable (related party)		9	0
Accrued expenses		(140)	(7,493)
Deferred revenue			0
Operating lease liabilities		(356)	(178)
Deferred interest payable		0	1,517
Other		855	0
Net cash used in operating activities		(61,984)	(66,811)
Cash flows from investing activities:
Purchases of marketable securities		(14,973)	0
Maturities of marketable securities		3,000	0
Purchases of property and equipment		(151)	(139)
Net cash used in investing activities		(12,124)	(139)
Cash flows from financing activities:
Proceeds from related party debt financing		80,000	0
Proceeds from stock option exercises		2,190	314
Net cash provided by financing activities		82,190	137,610
Net change in cash, cash equivalents and restricted cash		8,082	70,660
Cash, cash equivalents and restricted cash, beginning of period		78,018	157,199
Cash, cash equivalents and restricted cash, end of period		86,100	227,859
Non-cash financing activities:
Deferred financing costs included in accrued expenses		0	212
Private Placement | Cowen and Company, LLC
Cash flows from financing activities:
Cash proceeds from issuance of common shares		0	2,546
Public Offering
Cash flows from financing activities:
Cash proceeds from issuance of common shares		$ 0	$ 134,750

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