Subsequent Events - Additional Information (Detail)						1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 16, 2016 shares	Feb. 12, 2016 shares	Jan. 27, 2016 shares	Jan. 08, 2016 USD ($) $ / shares shares	Jan. 05, 2016 fund shares	Jul. 31, 2015 shares	Mar. 25, 2016 shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) shares	Apr. 30, 2015 $ / shares	Mar. 05, 2015 $ / shares
Subsequent Event [Line Items]
Stock issuance costs | $								$ 575,181	$ 2,117,217
Warrants cashless exercised								43,720
Common stock, shares issued								14,017,909	6,769,106
Series D Warrants [Member]
Subsequent Event [Line Items]
Number of warrants								1,280,324
Exercise price of warrants (in dollars per share) | $ / shares								$ 2.46
Series B Warrant Liability [Member]
Subsequent Event [Line Items]
Number of warrants								116,580
Exercise price of warrants (in dollars per share) | $ / shares											$ 6.50
Warrants cashless exercised								1,713,045
Series C Warrants [Member]
Subsequent Event [Line Items]
Number of common stock purchased upon issuance of warrants								590,415
Exercise price of warrants (in dollars per share) | $ / shares										$ 6.25	$ 6.25
Warrants cashless exercised						905
Subsequent event [Member]
Subsequent Event [Line Items]
Number of funds | fund					2
Common stock, shares issued							485,202
Subsequent event [Member] | Series D Warrants [Member]
Subsequent Event [Line Items]
Proceeds from warrants | $				$ 5,000,000
Stock issuance costs | $				$ 500,000
Subsequent event [Member] | Series D Warrants [Member] | Sabby Management, LLC [Member]
Subsequent Event [Line Items]
Number of warrants issued				1,471,622
Subsequent event [Member] | Series D Warrants [Member] | Maxim Group Llc [Member]
Subsequent Event [Line Items]
Number of warrants issued				58,865
Subsequent event [Member] | Series B Warrant Liability [Member]
Subsequent Event [Line Items]
Warrants cashless exercised							102,300
Number of warrants expired in period		14,280
Subsequent event [Member] | Series A convertible preferred stock [Member]
Subsequent Event [Line Items]
Number of shares converted	1,665		1,665		1,665
Convertible preferred stock, shares issued				5,445
Convertible preferred stock, stated value (in dollars per share) | $ / shares				$ 1,000
Convertible preferred stock, par value (in dollars per share) | $ / shares				$ 0.001
Subsequent event [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Number of shares issued upon conversion	900,000		900,000		900,000