Stock-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Number of Shares
Beginning balance (in shares)	2,718,971	2,641,198
Options granted (in shares)	26,236	638,983
Options exercised (in shares)	(323,701)	(444,924)
Options canceled and forfeited (in shares)	(15,549)	(116,286)
Ending balance (in shares)	2,405,957	2,718,971
Options vested and exercisable (in shares)	2,069,020
Options vested and expected to vest (in shares)	2,390,755
Weighted-Average Exercise Price
Beginning balance (in dollars per share)	$ 8.02	$ 4.27
Options granted (in dollars per share)	17.31	20.89
Options exercised (in dollars per share)	4.52	3.36
Options canceled and forfeited (in dollars per share)	17.07	11.30
Ending balance (in dollars per share)	8.54	$ 8.02
Options vested and exercisable (in dollars per share)	6.85
Options vested and expected to vest (in dollars per share)	$ 8.36
Weighted-Average Remaining Contractual Life and Aggregate Intrinsic Value
Weighted-average remaining contractual life, options outstanding (in years)	5 years 9 months 18 days
Weighted-average remaining contractual life, options vested and exercisable (in years)	5 years 4 months 24 days
Weighted-average remaining contractual life, options vested and expected to vest (in years)	6 years
Aggregate intrinsic value, options outstanding	$ 51,402
Aggregate intrinsic value, options vested and exercisable	47,689
Aggregate intrinsic value, options vested and expected to vest	$ 51,493