Warrant Exercise (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		127 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014
Class of Warrant or Right [Line Items]
Warrant exercised	0
Liability Reclassed Equity
Cash Received		101	13,278
Equity Warrants
Class of Warrant or Right [Line Items]
Warrant exercised		49,315
Common Stock Issued
Class of Warrant or Right [Line Items]
Warrant exercised		49,315
Cash exercises
Class of Warrant or Right [Line Items]
Liability Reclassed Equity
Cash Received		101
Cash exercises | Equity Warrants
Class of Warrant or Right [Line Items]
Warrant exercised		49,315
Cash exercises | Common Stock Issued
Class of Warrant or Right [Line Items]
Warrant exercised		49,315
Cashless Exercise
Class of Warrant or Right [Line Items]
Liability Reclassed Equity