Redeemable Convertible Preferred Stock - Summary of Preferred Stock (Details) - USD ($)	May 11, 2015	May 31, 2015
Class Of Stock [Line Items]
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
Preferred Shares Before IPO	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
Preferred Shares Before IPO	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 Redeemable Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion of preferred stock into common stock at initial public offering	$ 30,370,273
Preferred Shares Before IPO	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
Preferred Shares Before IPO	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	374,632
Cumulative Dividends	$ 8,808,065