Warrants - Additional Information (Details) - USD ($)				3 Months Ended	12 Months Ended
	May. 11, 2015	Jan. 15, 2015	Aug. 22, 2014	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	May. 31, 2015	Dec. 30, 2014
Class Of Warrant Or Right [Line Items]
Fair value of common stock								$ 0.13
Expected risk-free interest rate				1.60%		1.20%
Expected volatility				75.00%		70.00%
Expected term				7 years		4 years 1 month 6 days
Expected dividend yield				0.00%
Fair value of warrants								$ 741,828
Common stock, at the initial public offering price per shares	$ 14.00
Preferred stock, shares issued				0	0	0
Class of Warrant or Right, Outstanding					0
Fair value of convertible preferred stock warrant liability				$ 730,543	$ 0	$ 730,543
Loss on change in fair value of convertible preferred stock warrants					$ 239,683	$ 388,936
IPO
Class Of Warrant Or Right [Line Items]
Common stock, at the initial public offering price per shares	$ 14.00
Series E Stock
Class Of Warrant Or Right [Line Items]
Fair value of common stock			$ 0.31
Warrants exercise price			$ 0.2189
Expected risk-free interest rate			1.60%
Expected volatility			70.00%
Expected term			4 years 6 months
Expected dividend yield			8.00%
Series C-1 Redeemable Convertible Preferred Stock
Class Of Warrant Or Right [Line Items]
Warrants exercise price					$ 37.16
Preferred stock warrants forfeited and cancelled	1,290,350
Class of Warrant or Right, Outstanding				1,290,350		1,290,350
Series C-2 Redeemable Convertible Preferred Stock
Class Of Warrant Or Right [Line Items]
Warrants exercise price					24.23
Class of Warrant or Right, Outstanding				157,912		157,912
Series C-2 Redeemable Convertible Preferred Stock | IPO
Class Of Warrant Or Right [Line Items]
Warrants issued to acquire shares	1,488
Warrants exercise price	$ 24.23
Series D Convertible Preferred Stock
Class Of Warrant Or Right [Line Items]
Warrants exercise price					1.07
Common stock, at the initial public offering price per shares					$ 14.00
Preferred stock, shares issued					723,050
Class of Warrant or Right, Outstanding				769,059	769,059	769,059
Proceeds from exercise of E warrants					$ 1,752
Conversion of stock, shares issued	6,729
Series E Loan Warrants
Class Of Warrant Or Right [Line Items]
Warrants issued to acquire shares			2,512,562				23,396
Warrants exercise price	$ 23.51		$ 0.2189				$ 23.51
Warrants expiration date					Aug. 22, 2024
Warrants exercise price			$ 0.12
Fair value of warrants			$ 301,507	$ 301,507		$ 301,507
Series E Loan Warrants | IPO
Class Of Warrant Or Right [Line Items]
Warrants issued to acquire shares	23,396
Convertible Note Warrants
Class Of Warrant Or Right [Line Items]
Warrants issued to acquire shares		9,311,586
Warrants exercise price		$ 0.2189			$ 14.00
Warrants expiration date					Jan. 15, 2022
Aggregate consideration		$ 1,354
Convertible Note Warrants | IPO
Class Of Warrant Or Right [Line Items]
Warrants issued to acquire shares	144,772
Warrants exercise price	$ 14.00
Class of Warrant or Right, Outstanding					144,772