Preferred Stock Warrant Liability - Additional Information (Detail) - USD ($)		1 Months Ended	12 Months Ended
	Aug. 17, 2015	Sep. 30, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Jul. 01, 2015	Jun. 26, 2015	Dec. 31, 2013
Class of Stock [Line Items]
Fair value of warrant issuance			$ 0	$ 1,582,000	$ 0			$ 164,000
Loss from revaluation of preferred stock warrant liability			7,000	1,418,000
Common Stock [Member]
Class of Stock [Line Items]
Warrants exercise price per share	$ 1.78
Proceeds from exercise of warrant	$ 164,000
Common Stock [Member] | Initial Public Offering ("IPO") [Member]
Class of Stock [Line Items]
Public offering price per share						$ 18.00	$ 18.00
Series A-2 Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Warrants issued to purchase of stock		92,127
Warrants exercise price per share		$ 1.78
Class of warrant or right, contractual term		10 years
Fair value of warrant issuance		$ 156,000	$ 17,260	$ 17,180