Consolidated Statements of Operations - USD ($) $ in Thousands	2 Months Ended	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2018	Mar. 31, 2017
Operating expenses:
Research and development (includes $3,674, $3,893 and $0 of share-based compensation expense for the years ended March 31, 2018 and 2017 and the period from February 2, 2016 (Date of Inception) to March 31, 2016, respectively)	$ 0	$ 116,832	$ 43,500
General and administrative (includes $7,909, $4,824 and $987 of share-based compensation expense for the years ended March 31, 2018 and 2017 and the period from February 2, 2016 (Date of Inception) to March 31, 2016, respectively)	1,657	24,231	12,357
Total operating expenses	1,657	141,063	55,857
Changes in the fair value of the Takeda warrant liability	0	0	27,518
Interest expense	0	2,046	0
Other (income) expense	0	(67)	139
Loss before income taxes	(1,657)	(143,042)	(83,514)
Income tax expense (benefit)	0	213	(74)
Net loss	$ (1,657)	$ (143,255)	$ (83,440)
Net loss per common share — basic and diluted (in USD per share)	$ (0.04)	$ (2.41)	$ (1.70)
Weighted average common shares outstanding — basic and diluted (in shares)	37,231,342	59,520,747	49,184,668