Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017
Payables and Accruals [Abstract]
Research and development expenses	$ 10,225	$ 9,737
Salaries, bonuses, and other compensation expenses	400	797
Legal expenses	410	481
Other expenses	257	963
Total accrued expenses	$ 11,292	$ 11,978