Net Loss Per Share of Common Stock - Antidilutive Securities Excluding from Computation of Earnings Per Share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 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	4,238,304	3,838,635	4,238,304	3,838,635
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	2,652,683	3,024,743	2,652,683	3,024,743
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	1,333,501	564,638	1,333,501	564,638
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	9,732	46,811	9,732	46,811
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	124,266	84,321	124,266	84,321
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	118,122	118,122