Capital Stock - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended									12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Apr. 30, 2016	Dec. 31, 2015	May 31, 2015	Feb. 28, 2015	Aug. 31, 2014	Dec. 31, 2013	Jul. 31, 2012	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stockholders Equity [Line Items]
Common stock, shares authorized				250,000,000						250,000,000	250,000,000
Preferred stock, shares authorized										10,000,000
Common stock, voting rights										The holders of the Company’s common stock have one vote per share.
Voting power required for amendment or repeal of any provisions										66.67%
Common stock shares issued and sold	1,240,000	1,054,023	186,071	102,500			100,000	71,013	41,667
Proceeds from issuance of common stock and common stock warrants	$ 15,600	$ 9,500	$ 3,500	$ 9,970	$ 17,200	$ 6,700	$ 18,000		$ 57,400	$ 28,661	$ 33,820	$ 18,000
Stock price		$ 9.00
Additional purchase of common stock shares										4,036,683
Common stock units issued					215,000	110,833
Net proceeds from common stock issued								$ 26,400
Underwriting discounts commissions and other offering costs								$ 2,000
2014 Warrants
Stockholders Equity [Line Items]
Warrants, exercise price							$ 36.20			$ 36.20
Warrants, Expiration date										Aug. 05, 2019
Additional purchase of common stock shares							50,000			50,000
2013 Warrants
Stockholders Equity [Line Items]
Warrants, exercise price										$ 49.80
Warrants, Expiration date										Dec. 16, 2018
Additional purchase of common stock shares								71,013		71,013
Series I Warrant
Stockholders Equity [Line Items]
Warrants issued to purchase same number of common stock	712,503
Warrants, exercise price										$ 11.00
Warrants, Expiration date										Sep. 13, 2021
Series J Warrant
Stockholders Equity [Line Items]
Warrants issued to purchase same number of common stock	185,000
Series F Warrant
Stockholders Equity [Line Items]
Warrants, exercise price										$ 5.80
Warrants, Expiration date										Apr. 01, 2021
Additional purchase of common stock shares			514,644
Series G Warrant
Stockholders Equity [Line Items]
Additional purchase of common stock shares			328,571
Series H Warrant
Stockholders Equity [Line Items]
Warrants, Expiration date										Oct. 01, 2016
Additional purchase of common stock shares			1,029,286
Series D Warrant
Stockholders Equity [Line Items]
Warrants, exercise price										$ 2.00
Warrants, Expiration date										Dec. 11, 2020
Additional purchase of common stock shares				502,500
Series E Warrant
Stockholders Equity [Line Items]
Additional purchase of common stock shares				400,000
Series C Warrant
Stockholders Equity [Line Items]
Warrants, exercise price					$ 27.80
Warrants, Expiration date										May 19, 2020
Additional purchase of common stock shares					21,500
Series A Warrant
Stockholders Equity [Line Items]
Warrants, exercise price										$ 5.80
Warrants, Expiration date										Feb. 03, 2020
Additional purchase of common stock shares						110,833
Series B Warrant
Stockholders Equity [Line Items]
Warrants, Expiration date										Aug. 03, 2015
Additional purchase of common stock shares						110,833