Redeemable Convertible Preferred Stock - Schedule of Conversion of Preferred Stock into Common Stock (Details)	12 Months Ended
	Dec. 31, 2014
Series B Redeemable Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion, Preferred Shares Converted	5,129,912
Conversion of stock, shares issued	57,307
Series C-1 Redeemable Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion, Preferred Shares Converted	2,997,838
Conversion of stock, shares issued	43,330
Series C-2 Redeemable Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion, Preferred Shares Converted	9,156,279
Conversion of stock, shares issued	86,292
Series D Redeemable Convertible Preferred Stock
Class Of Stock [Line Items]
Conversion, Preferred Shares Converted	4,233,419
Conversion of stock, shares issued	39,420