FIXED ASSETS - Schedule of Fixed Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 99,799		$ 89,634
Less – accumulated depreciation	(75,935)		(66,536)
Fixed assets, net	23,864		23,098
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Fixed assets, gross	3,739		3,693
Furniture and fixtures | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Furniture and fixtures | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
Computer equipment and internal use software
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Fixed assets, gross	69,259		62,045
Computer equipment and internal use software | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Computer equipment and internal use software | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Demonstration and spare part units
Property, Plant and Equipment [Line Items]
Estimated useful life	2 years
Fixed assets, gross	12,092		10,755
Leasehold improvements
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 14,709	[1]	$ 13,141	[1]
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	12 years

[1] Leasehold improvements are depreciated over the shorter of the lease term or anticipated useful life of the improvement.