SHARE-BASED COMPENSATION (Details) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
	Sep. 12, 2019 shares	Sep. 30, 2019 USD ($) $ / shares shares	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) $ / shares shares	Sep. 30, 2018 USD ($)
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		$ 15,857	$ 17,418	$ 28,600	$ 30,383
ESPP
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Percentage of common stock price for employees				85.00%
Additional shares (in shares) | shares				297,635
Share price (in USD per share) | $ / shares		$ 22.15		$ 22.15
Maximum | Incentive Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Term of options granted, years				5 years
2019 Equity Incentive Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Number of shares reserved for issuance (in shares) | shares	6,794,651
Number of new shares (in shares) | shares	5,500,000
Reduction for each share of common stock pursuant to option	1
Reduction for each share of common stock pursuant to other than option	2.76
Number of shares available for grant (in shares) | shares		6,965,972		6,965,972
Share-based awards generally vest, years				4 years
Percentage of incentive stock options granted				110.00%
2019 Equity Incentive Plan | Minimum
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Percentage of fair market value of common stock				100.00%
Percentage of voting stock				10.00%
2019 Equity Incentive Plan | Maximum
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Term of options granted, years				7 years
Amended 2007 Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Number of shares reserved for issuance (in shares) | shares	1,294,651
Cost of product revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		$ 345	544	$ 612	813
Cost of service revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		1,842	1,845	3,309	3,175
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		4,820	5,414	8,639	9,565
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		5,288	6,043	9,423	10,402
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense		$ 3,562	$ 3,572	$ 6,617	$ 6,428