Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Reconciliation of Warrant Liability Measured at Fair Value (Detail)

v2.4.0.8
Stockholders' Equity - Reconciliation of Warrant Liability Measured at Fair Value (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Equity [Abstract]      
Beginning Balance $ 32,558 $ 9,209  
Exercise of common stock warrants (11,462) (27,867)  
Change in fair value of common stock warrants 2,325 51,216 (4,358)
Ending Balance $ 23,421 $ 32,558 $ 9,209