Organization and Basis of Presentation - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended	0 Months Ended
	Dec. 31, 2014	Dec. 02, 2014	Feb. 11, 2014	Dec. 31, 2013
Organization And Basis Of Presentation [Line Items]
Collaboration and license agreement, date	May 28, 2013
Accumulated deficit	$ (91,750)			$ (57,594)
Proceeds from issuance of common stock	70,237
Issuance of warrants		871,840
Initial Public Offering ("IPO") [Member]
Organization And Basis Of Presentation [Line Items]
Issuance of common stock		1,743,680	5,750,000
Proceeds from issuance of common stock		$ 18,200	$ 50,200
Issuance of warrants		871,840