Warrant Exercise (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended		109 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012
Class of Warrant or Right [Line Items]
Liability Reclassed to Equity	$ 412	$ 303
Cash Received	330	12,399	13,079
Cash exercises [Member]
Class of Warrant or Right [Line Items]
Cash Received	330	12,399
Cashless exercises [Member]
Class of Warrant or Right [Line Items]
Liability Reclassed to Equity	$ 412	$ 303
Equity Warrants [Member]
Class of Warrant or Right [Line Items]
Warrant exercised	186,297	2,351,417
Equity Warrants [Member] | Cash exercises [Member]
Class of Warrant or Right [Line Items]
Warrant exercised	161,639	2,311,585
Equity Warrants [Member] | Cashless exercises [Member]
Class of Warrant or Right [Line Items]
Warrant exercised	24,658	39,832
Liability Warrants [Member]
Class of Warrant or Right [Line Items]
Warrant exercised	373,617	165,551
Liability Warrants [Member] | Cashless exercises [Member]
Class of Warrant or Right [Line Items]
Warrant exercised	373,617	165,551
Common Stock Issued [Member]
Class of Warrant or Right [Line Items]
Warrant exercised	259,660	2,377,571
Common Stock Issued [Member] | Cash exercises [Member]
Class of Warrant or Right [Line Items]
Warrant exercised	161,639	2,311,585
Common Stock Issued [Member] | Cashless exercises [Member]
Class of Warrant or Right [Line Items]
Warrant exercised	98,021	65,986