Common Stock and Stock-Based Awards - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Equity [Abstract]
Number of Shares, Beginning Balance	10,037,130
Number of Shares, Granted	1,924,406
Number of Shares, Exercised	(104,184)
Number of Shares, Forfeited	(260,973)
Number of Shares, Ending Balance	11,596,379	10,037,130
Number of Shares, Options exercisable	3,974,020
Weighted Average Exercise Price, Beginning Balance	$ 9.54
Weighted Average Exercise Price, Granted	24.13
Weighted Average Exercise Price, Exercised	3.56
Weighted Average Exercise Price, Forfeited	23.58
Weighted Average Exercise Price, Ending Balance	11.70	$ 9.54
Weighted Average Exercise Price, Options exercisable	$ 12.66
Weighted Average Remaining Contractual Term, Outstanding	7 years 11 months 8 days	7 years 10 months 13 days
Weighted Average Remaining Contractual Term, Options exercisable	6 years 29 days
Aggregate Intrinsic Value, Outstanding	$ 122,100	$ 156,627
Aggregate Intrinsic Value, Options exercisable	$ 37,985