Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 297,961	$ 281,098
Research and development and other tax credit carryforwards	11,965	11,878
Accruals and reserves	26,222	28,088
Fixed assets and intangible assets	2,250	2,393
Other	12,454	14,494
Gross deferred tax assets	350,852	337,951
Valuation allowance	(315,092)	(301,393)
Total deferred tax assets	35,760	36,558
Intercompany debt	(25,841)	(27,117)
Other	(9,637)	(9,408)
Total deferred tax liabilities	(35,478)	(36,525)
Net deferred tax asset	$ 282	$ 33