Redeemable Convertible Preferred Stock - Schedule of Preferred Stock (Details) - USD ($)		9 Months Ended
	May. 11, 2015	Sep. 30, 2015
Class Of Stock [Line Items]
Conversion of preferred stock into common stock at initial public offering		$ 57,356,049
Carrying value including cumulative dividends	$ 57,356,049
Preferred shares before IPO including cumulative dividends	217,515,139
Common shares after IPO including dividends	2,508,824
Series A Redeemable Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion of preferred stock into common stock at initial public offering	$ 1,403,007	$ (1,403,007)
Preferred Shares Before IPO	1,292,084	(1,292,084)
Common Shares After IPO	38,973
Series B Preferred Stock
Class Of Stock [Line Items]
Conversion of preferred stock into common stock at initial public offering	$ 2,100,149	$ (2,100,149)
Preferred Shares Before IPO	6,789,712	(6,789,712)
Common Shares After IPO	75,835
Series C-1
Class Of Stock [Line Items]
Conversion of preferred stock into common stock at initial public offering	$ 4,569,063
Preferred Shares Before IPO	13,242,612
Common Shares After IPO	191,406
Series C-2
Class Of Stock [Line Items]
Conversion of preferred stock into common stock at initial public offering	$ 2,225,619
Preferred Shares Before IPO	9,948,331
Common Shares After IPO	93,757
Series D Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion of preferred stock into common stock at initial public offering	$ 30,370,273	$ (38,163,280)
Preferred Shares Before IPO	140,252,678	(140,252,678)
Common Shares After IPO	1,305,984
Series E Preferred Stock
Class Of Stock [Line Items]
Conversion of preferred stock into common stock at initial public offering	$ 7,879,873	$ (8,894,931)
Preferred Shares Before IPO	45,989,722	(45,989,722)
Common Shares After IPO	428,237
Preferred Shares Excluding Dividends
Class Of Stock [Line Items]
Conversion of preferred stock into common stock at initial public offering	$ 48,547,984
Preferred Shares Before IPO	217,515,139
Common Shares After IPO	2,134,192
Series D And E Preferred Stock Cumulative Dividends
Class Of Stock [Line Items]
Common Shares After IPO	374,632
Cumulative Dividends	$ 8,808,065