Stock-Based Compensation - Schedule of Stock Options Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Options Available for Grant
Number of options beginning balance	2,695,110
Authorized	1,160,000
Granted	(1,312,610)
Exercised	0
Cancelled	295,484
Repurchased	13,899
Number of options ending balance	2,851,883	2,695,110
Outstanding Options
Outstanding at beginning of period	2,429,859
Granted	1,312,610
Exercised	(281,024)
Cancelled	(295,484)
Outstanding at end of period	3,165,961	2,429,859
Options Outstanding, Number of Shares, Vested and exercisable	1,124,222
Options Outstanding, Number of Shares, Vested and expected to vest	2,939,089
Weighted Average Exercise Price
Beginning Balance	$ 5.31
Granted	11.30
Exercised	1.61
Cancelled	8.46
Repurchased	0.35
Ending Balance	7.83	$ 5.31
Weighted-Average Exercise Price, Vested and exercisable	5.16
Weighted-Average Exercise Price, Vested and expected to vest	$ 7.54
Options Outstanding, Weighted-Average Remaining Contractual Term (in years)	8 years 5 months 12 days	8 years 10 months 9 days
Options Outstanding, Weighted-Average Remaining Contractual Term, Vested and exercisable (in years)	7 years 10 months 17 days
Options Outstanding, Weighted-Average Remaining Contractual Term, Vested and expected to vest (in years)	8 years 4 months 17 days
Options Outstanding, Aggregate Intrinsic Value	$ 8,875	$ 25,646
Options Outstanding, Aggregate Intrinsic Value, Vested and exercisable	5,433
Options Outstanding, Aggregate Intrinsic Value, Vested and expected to vest	$ 8,864