Number of Warrants Outstanding (Detail)	Jun. 30, 2014	Dec. 31, 2013
Class of Warrant or Right [Line Items]
Warrant outstanding	10,496,467	10,539,767
Liability
Class of Warrant or Right [Line Items]
Warrant outstanding	8,235,076	8,235,076
Equity
Class of Warrant or Right [Line Items]
Warrant outstanding	2,261,391	2,304,691