Condensed Consolidated Statements of Operations - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Collaboration revenue		$ 22,354	$ 0
Total revenues		59,317	0	0
Research and development	[1]	136,713	192,560	222,607
Selling, general and administrative	[2]	181,423	82,327	42,219
Total operating costs and expenses		320,101	274,887	264,826
Loss from operations		(260,784)	(274,887)	(264,826)
Interest expense	[3]	10,401	12,663	8,821
Loss on extinguishment of debt		0	4,851	0
Interest income		(211)	(2,552)	(881)
Foreign currency transaction (gain) loss		(16,176)	(1,621)	309
Loss before income taxes		(254,798)	(288,228)	(273,075)
Income tax expense		336	761	476
Net loss		$ (255,134)	$ (288,989)	$ (273,551)
Net loss per common share — basic and diluted (in USD per share)		$ (2.83)	$ (3.37)	$ (4.09)
Weighted average common shares outstanding — basic and diluted (in shares)		90,036,459	85,839,303	66,910,060
Product revenue, net
Revenues		$ 3,630	$ 0	$ 0
Cost of product revenue
Cost of revenue		301	0	0
Collaboration expense to Pfizer
Cost of revenue		1,664	0	0
License and Service
Revenues		33,333	0	$ 0
Term Loan | Letter Agreement with Sumitomo Dainippon Pharma, Co., Ltd.
Loss on extinguishment of debt			4,900
Sumitomo Dainippon Pharma, Co., Ltd. and Sunovion Pharmaceuticals Inc. | Majority Shareholder
Research and development		58
Selling, general and administrative		5,330
Sumitomo Dainippon Pharma Co., Ltd. | Majority Shareholder | Term Loan | Letter Agreement with Sumitomo Dainippon Pharma, Co., Ltd.
Interest expense		$ 9,766	$ 1,441

[1] Includes $58 of expense (inclusive of third-party pass-through costs) for the year ended March 31, 2021 to related parties (see Note 6).

[2] Includes $5,330 of expense (inclusive of third-party pass-through costs) for the year ended March 31, 2021 to related parties (see Note 6).

[3] Includes $9,766 and $1,441 of interest expense under the Sumitomo Dainippon Pharma Loan Agreement for the years ended March 31, 2021 and 2020. (see Note 6(A)).