Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (13,883)	$ (18,355)	$ (46,084)	$ (48,293)
Other comprehensive loss:
Unrealized loss on available-for-sale securities, net of tax	(86)	(213)	(87)	(186)
Comprehensive loss	$ (13,969)	$ (18,568)	$ (46,171)	$ (48,479)