Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Income Tax Contingency [Line Items]
Tax at federal statutory rate	35.00%	35.00%	35.00%
Cumulative undistributed earnings of the Company's foreign subsidiaries	$ 14,900
Valuation allowance	488,646	$ 475,545
Increase in valuation allowance	13,200
Unrecognized tax benefits that would impact effective tax rate	0
Unrecognized tax benefits	44,935	$ 45,079	$ 44,231	$ 43,382
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards	1,233,000
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards	447,000
Research Tax Credit Carryforward | Federal
Income Tax Contingency [Line Items]
Tax credit carryforwards	64,600
Research Tax Credit Carryforward | State
Income Tax Contingency [Line Items]
Tax credit carryforwards	$ 30,300