Commitments and Contingencies (Detail) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Derivative Liability, Notional Amount	$ 43,000,000	$ 48,000,000
Derivative, Gain (Loss) on Derivative, Net	$ 138,000	$ 354,000