Preferred Stock and Warrants (Summary of Preferred Stock Terms) (Parenthetical) (Detail)	9 Months Ended
	Sep. 30, 2015 $ / shares
Series A Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, liquidation Value per share	$ 4.50
Series B Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, liquidation Value per share	$ 4.00
Preferred Stock Dividend Frequency Of Payment	10%—Quarterly Commencing March 31, 2001
Preferred stock, dividend date of commencement	Mar. 31, 2001
Series C Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, liquidation Value per share	$ 3.00
Preferred Stock Dividend Frequency Of Payment	10% Quarterly Commencing March 31, 2002
Preferred stock, dividend date of commencement	Mar. 31, 2002
Series D Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, liquidation Value per share	$ 1,000
Preferred Stock Dividend Frequency Of Payment	10% Quarterly Commencing March 31, 2002
Preferred stock, dividend date of commencement	Apr. 30, 2002
Series E Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, liquidation Value per share	$ 22.00
Preferred Stock Dividend Frequency Of Payment	10% Quarterly Commencing May 31, 2002
Preferred stock, dividend date of commencement	May 31, 2002