Convertible Preferred Stock - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	May. 15, 2015	Dec. 31, 2014
Class Of Stock [Line Items]
Preferred stock, shares outstanding	0		0
Series F Convertible Preferred Stock To Common Stock [Member]
Class Of Stock [Line Items]
Converted preferred stock shares		222,222
Preferred stock, shares outstanding		10,000
Convertible Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred stock value outstanding	$ 0
Private Tobira [Member] | Series B Preferred Stock [Member]
Class Of Stock [Line Items]
Conversion of notes and accrued interest into preferred stock	3,532,756
Conversion price of common stock	$ 1.7742
Private Tobira [Member] | Series A and B Preferred Stock [Member]
Class Of Stock [Line Items]
Converted preferred stock shares	3,916,772
Private Tobira [Member] | Series A Preferred Stock [Member]
Class Of Stock [Line Items]
Conversion price of common stock	$ 1.7742
Regado [Member]
Class Of Stock [Line Items]
Number of common shares exchanged	10,654,460