Net Loss Per Common Share - Schedule of Potentially Dilutive Securities Excluded from Diluted Net Loss Per Common Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Antidilutive Securities
Potentially dilutive securities excluded from diluted net loss per common share	1,758,105	4,016,568	1,758,105	4,016,568
Redeemable Convertible Preferred Stock
Antidilutive Securities
Potentially dilutive securities excluded from diluted net loss per common share		2,486,199		2,486,199
Options to Purchase Common Stock
Antidilutive Securities
Potentially dilutive securities excluded from diluted net loss per common share	1,595,415	1,262,294	1,595,415	1,262,294
RSU
Antidilutive Securities
Potentially dilutive securities excluded from diluted net loss per common share	10,000		10,000
Common Stock Subject to Repurchase
Antidilutive Securities
Potentially dilutive securities excluded from diluted net loss per common share	125,000	240,385	125,000	240,385
Redeemable Convertible Preferred Stock Warrants
Antidilutive Securities
Potentially dilutive securities excluded from diluted net loss per common share		27,690		27,690
Common Stock Warrants
Antidilutive Securities
Potentially dilutive securities excluded from diluted net loss per common share	27,690		27,690