Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Operating expenses:
Research and development (includes $679 and $814 of share-based compensation expense for the three months ended September 30, 2017 and 2016 and $1,539 and $1,789 for the six months ended September 30, 2017 and 2016, respectively)	$ 24,170	$ 3,753	$ 41,878	$ 18,326
General and administrative (includes $2,070 and $1,336 of share-based compensation expense for the three months ended September 30, 2017 and 2016 and $3,411 and $2,982 for the six months ended September 30, 2017 and 2016, respectively)	6,141	2,967	10,323	5,529
Total operating expenses	30,311	6,720	52,201	23,855
Other expenses:
Changes in the fair value of the warrant liability	0	27,984	0	29,817
Other (income) expense	(138)	0	204	0
Loss before provision for income taxes	(30,173)	(34,704)	(52,405)	(53,672)
Income tax (benefit) expense	(265)	8	820	11
Net loss	$ (29,908)	$ (34,712)	$ (53,225)	$ (53,683)
Net loss per common share — basic and diluted (in USD per share)	$ (0.50)	$ (0.82)	$ (0.90)	$ (1.29)
Weighted average common shares outstanding — basic and diluted (in shares)	59,459,500	42,512,254	59,353,966	41,646,657