Stockholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Common stock, par value (in dollars per share)		$ 0.0001		$ 0.0001	$ 0.0001
Compensation cost not yet recognized		$ 418,881		$ 418,881
Compensation cost not yet recognized, period for recognition				2 years 7 months 6 days
Series F Preferred Stock
Class of Stock [Line Items]
Shares converted (in shares)				(1,301.85)
Convertible preferred stock, shares issued upon conversion (in shares)		(495,000)		(495,000)
Series D Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)		14,052.93		14,052.93	17,202.65
Series E Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)		7,000		7,000	0
Series D Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)		14,052.93		14,052.93
Shares converted (in shares)				3,149.72
Series F Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)		5,819.15		5,819.15	0
2017 Offering
Class of Stock [Line Items]
Net proceeds from issuance of stock and warrants			$ 6,300,000
Net proceeds from issuance of stock and warrants			$ 7,000,000
2017 Offering | Series D Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)			19,458.90
2017 Offering | Series E Convertible Preferred Stock
Class of Stock [Line Items]
Shares issued during period (in shares)			7,000
Q3 2017 Offering | Series D Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)		14,052.93		14,052.93
Q3 2017 Offering | Series E Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares)		7,000		7,000
Q3 2017 Offering | Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, conversion price (in dollars per share)				$ 2.63
Dividends, preferred stock, total		$ 2,800,000
Q3 2017 Offering Tranche One
Class of Stock [Line Items]
Gross proceeds from issuance of equity		3,500,000
Net proceeds from issuance of stock and warrants		$ 3,300,000
Q3 2017 Offering Tranche One | Series F Preferred Stock
Class of Stock [Line Items]
Shares issued during period (in shares)		3,500
Shares issued (in dollars per share)		$ 1,000		$ 1,000
Shares of common stock available to purchase (in shares)		3,621		3,621
Number of shares authorized to be repurchased (in shares)		4,184,483		4,184,483
Gross proceeds from issuance of equity		$ 3,622,219
Q3 2017 Offering Tranche Two | Series F Preferred Stock
Class of Stock [Line Items]
Shares issued during period (in shares)		3,500
Shares issued (in dollars per share)		$ 1,000		$ 1,000
Q1 2017 Offering | Series E Convertible Preferred Stock
Class of Stock [Line Items]
Shares issued (in dollars per share)			$ 1,000
Q1 2017 Offering | Preferred Stock
Class of Stock [Line Items]
Dividends, preferred stock, total			$ 4,000,000
2017 Offerings
Class of Stock [Line Items]
Gross proceeds from issuance of equity				$ 14,000,000
Net proceeds from issuance of stock and warrants				$ 12,900,000
2017 Offerings | Preferred Stock
Class of Stock [Line Items]
Shares issued (in dollars per share)		$ 1,000		$ 1,000
Convertible preferred stock, conversion price (in dollars per share)				$ 2.63
June 2016 Offering
Class of Stock [Line Items]
Net proceeds from issuance of stock and warrants	$ 6,700,000
Net proceeds from issuance of stock and warrants	$ 7,500,000
June 2016 Offering | Series D Preferred Stock
Class of Stock [Line Items]
Shares issued (in dollars per share)	$ 1,000
Shares issued during period (in shares)	21,300
June 2016 Offering | Series C Preferred Stock
Class of Stock [Line Items]
Dividends, preferred stock, total	$ 19,800,000
Shares redeemed during period (in shares)	13,800
Common Stock
Class of Stock [Line Items]
Convertible preferred stock, shares issued upon conversion (in shares)		(809,103)		(809,103)
Common Stock | 2017 Offering
Class of Stock [Line Items]
Shares of common stock available to purchase (in shares)			1,250,000
Common stock, par value (in dollars per share)			$ 0.0001
Number of securities available to purchase by warrants or rights			2,934,484
Common Stock | June 2016 Offering
Class of Stock [Line Items]
Shares of common stock available to purchase (in shares)	1,475,069
Common stock, par value (in dollars per share)	$ 0.0001
Exercise price of warrants or rights (in dollars per share)	$ 13.52
Warrants | 2017 Offering
Class of Stock [Line Items]
Exercise price of warrants or rights (in dollars per share)			$ 5.6
Warrants | Q1 2017 Offering
Class of Stock [Line Items]
Exercise price of warrants or rights (in dollars per share)			$ 5.60
Class of warrant exercisable period			5 years
Warrants not settleable in cash, fair value disclosure			$ 3,490,000
Exercise price (in dollars per share)			$ 4.96
Expected volatility			70.20%
Risk free interest rate			2.04%
Expected term			5 years
Expected dividends			0.00%