Income Tax Benefit Attributable to Loss Before Income Taxes Differed (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Current:
Federal	$ 0	$ 0
State	0	0
Total	0	0
Deferred:
Federal	0	0
State	0	0
Deferred Income Tax Expense (Benefit)	0	0
Provision for income tax, net	$ 0	$ 0