Stock Plan and Stock-Based Compensation - Summary of Options Granted (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares
Shares Subject to Outstanding Options
Begining balance | shares	1,458,080
Options granted | shares	3,967,746
Options exercised | shares	(41,762)
Options forfeited or canceled | shares	(646,060)
Ending balance | shares	4,738,004
Options vested and expected to vest as of December 31, 2019 | shares	4,738,004
Options exercisable as of December 31, 2019 | shares	1,145,303
Weighted Average Exercise Price Per Share
Begining balance | $ / shares	$ 7.55
Options granted | $ / shares	9.66
Options exercised | $ / shares	4.85
Options forfeited or canceled | $ / shares	10.01
Ending balance | $ / shares	9.00
Options vested and expected to vest as of December 31, 2019 | $ / shares	9.00
Options exercisable as of December 31, 2019 | $ / shares	$ 8.52
Weighted Average Remaining Contractual Term (in years)	8 years 9 months 29 days
Options vested and expected to vest, Weighted Average Remaining Contractual Term (in years)	8 years 9 months 29 days
Options exercisable, Weighted Average Remaining Contractual Term (in years)	7 years 11 months 19 days
Aggregate Intrinsic Value | $	$ 8,174
Options vested and expected to vest, Aggregate Intrinsic Value | $	8,174
Options exercisable, Aggregate Intrinsic Value | $	$ 2,851