Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2012
Tax Credit Carryforward [Line Items]
Current tax benefit or provision	$ 0	$ 0	$ 0
Income taxes paid	0	0	0
Deferred tax benefit or provision	0	0	$ 0
Capital losses carryovers	24,300,000			$ 158,100,000
Net operating loss carryovers	$ 129,100,000
Capital loss carryovers begin to expire	Mar. 31, 2018
Net operating loss carryovers begin to expire	Mar. 31, 2032
Deferred tax asset	$ 60,747,000	112,442,000
Deferred tax assets, valuation allowance	67,286,000	121,486,000
Change in valuation allowance against net deferred tax assets	$ (54,200,000)	$ 85,500,000
Internal Revenue Service (IRS) [Member]
Tax Credit Carryforward [Line Items]
Statutory notification period	60 days