Stock-based Compensation Stock-Based Compensation Expense By Statement Of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	$ 6,657	$ 4,508	$ 13,008	$ 9,559
Cost of service revenue
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	473	440	864	800
Cost of product revenue
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	0	0	0	0
Research and development
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	1,314	863	2,651	1,750
Sales and marketing
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	2,568	1,751	5,215	3,666
General and administrative
Stock-based employee compensation expense related to employee stock options and employee stock purchases, pre tax	$ 2,302	$ 1,454	$ 4,278	$ 3,343