Significant Accounting Policies - Schedule Of Outstanding Potentially Dilutive Securities Excluded In Calculation Of Diluted Net Loss Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Significant Accounting Policies [Line Items]
Outstanding potentially dilutive securities excluded in calculation of diluted net loss per share	2,638,258	10,692,168
Redeemable Convertible Preferred Stock
Significant Accounting Policies [Line Items]
Outstanding potentially dilutive securities excluded in calculation of diluted net loss per share		9,132,024
Common Stock Options
Significant Accounting Policies [Line Items]
Outstanding potentially dilutive securities excluded in calculation of diluted net loss per share	2,525,055	1,075,284
Warrants to Purchase Common Stock
Significant Accounting Policies [Line Items]
Outstanding potentially dilutive securities excluded in calculation of diluted net loss per share	113,203
Warrants to Purchase Redeemable Convertible Preferred Stock
Significant Accounting Policies [Line Items]
Outstanding potentially dilutive securities excluded in calculation of diluted net loss per share		484,860