Summary of Significant Accounting Policies - Net Loss per Share (Details) - shares	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Anti-dilutive securities
Total shares excluded from diluted net loss per share applicable to common stockholders	8,544,035	3,711,150
Stock options
Anti-dilutive securities
Total shares excluded from diluted net loss per share applicable to common stockholders	4,651,250	3,711,150
Unvested Restricted Stock
Anti-dilutive securities
Total shares excluded from diluted net loss per share applicable to common stockholders	1,108,691
Warrants
Anti-dilutive securities
Total shares excluded from diluted net loss per share applicable to common stockholders	2,118,094
Convertible Preferred Stock
Anti-dilutive securities
Total shares excluded from diluted net loss per share applicable to common stockholders	666,000