Stock-based Compensation Stock-Based Compensation Expense By Statement Of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	$ 6,351	$ 5,051
Cost of service revenue
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	391	360
Cost of product revenue
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	0	0
Research and development
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	1,337	887
Sales and marketing
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	2,647	1,915
General and administrative
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	$ 1,976	$ 1,889