Estimated Fair Value for Each of the Convertible Preferred Stock Warrants (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	May 22, 2013	Dec. 31, 2012
Convertible Preferred Stock Warrants [Line Items]
Shares		81,075	81,075
Estimated Fair Value		$ 659	$ 683
Series A Preferred Stock
Convertible Preferred Stock Warrants [Line Items]
Expiration Date	Later of: (i) January 20, 2015 or (ii) 3 years after the closing of an initial public offering of our common stock
Exercise Price Per Share	10.00
Shares		4,740	4,740
Estimated Fair Value		35	36
Series B Preferred Stock
Convertible Preferred Stock Warrants [Line Items]
Expiration Date	Later of: (i) September 28, 2016 or (ii) 5 years after the closing of an initial public offering of our common stock
Exercise Price Per Share	13.10
Shares		76,335	76,335
Estimated Fair Value		$ 624	$ 647