Income Taxes - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Schedule Of Income Taxes [Line Items]
Federal	$ 4,700	$ 2,100
State	800	$ 400
Valuation allowance	44,654,000		$ 38,166,000
Federal net operating loss carry forwards	84,300,000
State and local net operating loss	154,500,000
Deferred tax assets tax credit carry forwards	$ 112,600,000
New York
Schedule Of Income Taxes [Line Items]
Deferred tax assets net operating loss carry forwards, expiration period	20 years
Federal
Schedule Of Income Taxes [Line Items]
Deferred tax assets net operating loss carry forwards, expiration period	20 years
Federal | Minimum
Schedule Of Income Taxes [Line Items]
Net operating loss carryforward, expiration year	2021
Federal | Maximum
Schedule Of Income Taxes [Line Items]
Net operating loss carryforward, expiration year	2036
Post-apportionment state | Minimum
Schedule Of Income Taxes [Line Items]
Net operating loss carryforward, expiration year	2015
Post-apportionment state | Maximum
Schedule Of Income Taxes [Line Items]
Net operating loss carryforward, expiration year	2036
Post-apportionment state | New York
Schedule Of Income Taxes [Line Items]
State and local net operating loss	$ 122,700,000
Pre-apportionment state | New York | Minimum
Schedule Of Income Taxes [Line Items]
Net operating loss carryforward, expiration year	2021
Pre-apportionment state | New York | Maximum
Schedule Of Income Taxes [Line Items]
Net operating loss carryforward, expiration year	2036