Reconciliation of Change in Value of Company's Warrants Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		398 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Class of Warrant or Right [Line Items]
Beginning balance	$ 79,116		$ 65,193
Increase in value of warrants	17,160	42,716	46,011	40,154	112,979
Ending balance	35,994		35,994		35,994
Warrant
Class of Warrant or Right [Line Items]
Reclassification to stockholders' equity upon exercise of warrants	$ (60,282)		$ (75,210)