Warrants - Summary of the Warrants Outstanding (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Aug. 31, 2015	Jun. 16, 2015
Private Placement Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date	Jun. 15, 2015
Warrants, Expiration Date	Jun. 15, 2020
Warrants, Classification	Equity
Warrants Outstanding	3,190,030	3,190,030
Warrants, Exercise Price	$ 7.56	$ 7.563
Hercules Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date	Jun. 15, 2015
Warrants, Expiration Date	Jun. 16, 2020
Warrants, Classification	Equity
Warrants Outstanding	25,150	25,150		25,150
Warrants, Exercise Price	$ 8.35			$ 8.35
MTS Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date	Aug. 31, 2015
Warrants, Expiration Date	Aug. 31, 2020
Warrants, Classification	Equity
Warrants Outstanding	30,000	30,000	30,000
Warrants, Exercise Price	$ 11.80		$ 11.80
Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants, Classification	Equity
Warrants Outstanding		1,219,000
Warrants, Exercise Price	$ 17.83
Series A Warrants [Member] | Minimum [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date	Mar. 31, 2014
Warrants, Expiration Date	Mar. 31, 2016
Series A Warrants [Member] | Maximum [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date	May 31, 2014
Warrants, Expiration Date	May 31, 2016
Representative's Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date	Mar. 21, 2014
Warrants, Expiration Date	Mar. 21, 2019
Warrants, Classification	Equity
Warrants Outstanding	37,100	37,100
Warrants, Exercise Price	$ 22.66
Underwriter's Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants, Issue Date	Mar. 21, 2014
Warrants, Expiration Date	Mar. 21, 2019
Warrants, Classification	Equity
Warrants Outstanding	2,160	2,160
Warrants, Exercise Price	$ 22.66