Net Loss Per Share of Common Stock - Antidilutive Securities Excluding from Computation of Earnings Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from the computation of diluted net loss per share	4,241,896	3,756,114
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from the computation of diluted net loss per share	2,700,554	3,047,130
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from the computation of diluted net loss per share	1,342,211	531,669
Shares subject to repurchase
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from the computation of diluted net loss per share	15,567	59,193
ESPP purchase rights
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from the computation of diluted net loss per share	65,442	0
Common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from the computation of diluted net loss per share	118,122	118,122