Net Loss per Common Share - Schedule of Potentially Dilutive Securities not Included in Calculation of Diluted Per Common Share (Details) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per common share would be anti-dilutive	13,214,469	11,452,541
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per common share would be anti-dilutive	11,790,706	10,207,557
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per common share would be anti-dilutive	1,361,902	1,181,323
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per common share would be anti-dilutive	61,861	63,661