Organization and Basis of Presentation - Additional Information (Detail) (USD $)	9 Months Ended		0 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Feb. 11, 2014 Initial Public Offering ("IPO") [Member]
Organization And Basis Of Presentation [Line Items]
Collaboration and license agreement, date	May 28, 2013
Accumulated deficit	$ (83,611,000)	$ (57,594,000)
Issuance of common stock			5,750,000
Proceeds from issuance of common stock			$ 50,200,000