Stockholders' Equity Stock-Based Compensation Expense By Statement Of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	$ 16,334	$ 9,347	$ 7,595
Tax benefit	0	0	0
Stock-based employee compensation expense related to employee stock options and employee stock purchases, net of tax	16,334	9,347	7,595
Cost of service revenue
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	1,159	692	372
Cost of product revenue
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	0	0	0
Research and development
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	2,914	1,495	967
Sales and marketing
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	6,133	3,748	2,217
General and administrative
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	$ 6,128	$ 3,412	$ 4,039