INCOME TAXES - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2014 USD ($) ownership_change
Income Taxes [Line Items]
Federal tax net operating loss carryforward	$ 347.4
Federal research and experimentation and orphan drug credit carryforward	68.1
State and local income tax expense	54.0
Deferred tax asset, exercise of stock options	1.8
Deferred tax assets valuation allowance	$ 219.8
Number of ownership changes | ownership_change	2
Stock Option
Income Taxes [Line Items]
Federal tax net operating loss carryforward	$ 16.7
Federal Tax
Income Taxes [Line Items]
Federal tax net operating loss carryforward	280.9
Federal research and experimentation and orphan drug credit carryforward	63.3
Restricted NOLs	67.2
Federal tax credits	4.8
Research and Development Credit Carryforwards
Income Taxes [Line Items]
Federal research and experimentation and orphan drug credit carryforward	$ 8.8