Summary of Significant Accounting Policies - Potentially dilutive securities (Details) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares	1,571,375	4,087,024
Stock Options
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares	1,482,819	516,756
Series A
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares		911,336
Series B
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares		2,570,376
Series B Redeemable Convertible Preferred Stock Warrants | Warrants
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares		88,556
Common Stock Warrants
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares	88,556