Warrant Exercise (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended		121 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Class of Warrant or Right [Line Items]
Liability Reclassed to Equity		$ 412
Cash Received	201	330	13,280
Equity Warrants
Class of Warrant or Right [Line Items]
Number Of Warrants Exercised	98,359	186,297
Liability Warrants
Class of Warrant or Right [Line Items]
Number Of Warrants Exercised		373,617
Common Stock Issued
Class of Warrant or Right [Line Items]
Number Of Warrants Exercised	98,359	259,660
Cash exercises
Class of Warrant or Right [Line Items]
Cash Received	201	330
Cash exercises | Equity Warrants
Class of Warrant or Right [Line Items]
Number Of Warrants Exercised	98,359	161,639
Cash exercises | Common Stock Issued
Class of Warrant or Right [Line Items]
Number Of Warrants Exercised	98,359	161,639
Cashless Exercise
Class of Warrant or Right [Line Items]
Liability Reclassed to Equity		$ 412
Cashless Exercise | Equity Warrants
Class of Warrant or Right [Line Items]
Number Of Warrants Exercised		24,658
Cashless Exercise | Liability Warrants
Class of Warrant or Right [Line Items]
Number Of Warrants Exercised		373,617
Cashless Exercise | Common Stock Issued
Class of Warrant or Right [Line Items]
Number Of Warrants Exercised		98,021