Stock-based compensation - Summary of Stock Option Activity Under Plan (Detail) shares in Thousands	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Shares (in thousands)
Outstanding at beginning of period (in shares) | shares	3,586
Granted (in shares) | shares	1,034
Exercised (in shares) | shares	(2)
Canceled or forfeited (in shares) | shares	(1,893)
Outstanding at end of period (in shares) | shares	2,725
Exercisable at end of period (in shares) | shares	1,231
Vested and expected to vest at end of period (in shares) | shares	2,725
Weighted- average exercise price per share
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 39.23
Granted (in dollars per share) | $ / shares	7.37
Exercised (in dollars per share) | $ / shares	1.04
Canceled or forfeited (in dollars per share) | $ / shares	40.74
Outstanding at end of period (in dollars per share) | $ / shares	27.78
Exercisable at end of period (in dollars per share) | $ / shares	45.69
Vested and expected to vest at end of period (in dollars per share) | $ / shares	$ 27.78