Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net loss	$ (67,487)	$ (50,149)	$ (40,225)
Other comprehensive income:
Unrealized gain on available-for-sale securities, net of tax	7	15
Comprehensive loss	$ (67,480)	$ (50,134)	$ (40,225)