Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Tax Credit Carryforward [Line Items]
Current tax benefit or provision	$ 0	$ 0	$ 0	$ 0
Income taxes paid	0	0	0	0
Deferred tax benefit or provision	0	$ 0	0	$ 0
Capital losses carryovers	24,300,000		24,300,000
Net operating loss carryovers	133,700,000		$ 133,700,000
Capital loss carryovers begin to expire			Mar. 31, 2018
Net operating loss carryovers begin to expire			Mar. 31, 2032
Deferred tax asset	62,561,000		$ 62,561,000
Deferred tax assets, valuation allowance	68,381,000		68,381,000
Change in valuation allowance against net deferred tax assets	$ 700,000		$ 1,100,000
Internal Revenue Service (IRS) [Member]
Tax Credit Carryforward [Line Items]
Statutory notification period			60 days