Summary of Significant Accounting Policies - Potentially dilutive securities (Details) - shares	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares	1,627,510	4,510,742
Stock Options
Potentially dilutive securities
Potentially dilutive securities excluded from computation of diluted weighted average shares	1,538,954	530,463
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		2,980,387
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