Net Loss Per Share - (Details) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in the diluted net loss per share calculation	3,998,727	19,949,188
Convertible preferred stock (as converted)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in the diluted net loss per share calculation		17,248,259
Common stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in the diluted net loss per share calculation	3,948,730	2,587,996
Common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in the diluted net loss per share calculation	49,997	62,936
Convertible preferred stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in the diluted net loss per share calculation		49,997