Stockholders' Equity - Summary of Stock Option Activity (Detail) - Options to purchase common stock - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Outstanding Options
Beginning balance (in shares)	7,892,857
Granted (in shares)	0
Exercised (in shares)	(117,420)
Forfeited / canceled (in shares)	0
Ending balance (in shares)	7,775,437	7,892,857
Vested and expected to vest (in shares)	7,775,437
Weighted Average Exercise Price
Beginning balance (in dollars per share)	$ 0.19
Granted (in dollars per share)	0
Exercised (in dollars per share)	0.29
Forfeited / canceled (in dollars per share)	0
Ending balance (in dollars per share)	$ 0.19	$ 0.19
Weighted Average Remaining Contractual Life (in years)
Weighted Average Remaining Contractual Life (in years)	7 years 1 month 28 days	7 years 3 months 21 days