Net Income (Loss) per Share - Basic and Diluted Net Income (Loss) per Share Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator:
Net loss	$ (64,735)	$ (56,624)	$ (48,330)	$ (35,465)	$ (121,359)	$ (83,795)
Denominator:
Weighted-average shares outstanding	92,255,416		91,659,829		92,224,382	91,593,845
Net loss per share applicable to common stockholders - basic	$ (0.70)		$ (0.53)		$ (1.32)	$ (0.91)
Net loss per share attributable to common stockholders, diluted	$ (0.70)		$ (0.53)		$ (1.32)	$ (0.91)
Stock Options to Purchase Common Stock [Member]
Anti-dilutive potential common stock equivalents excluded from the calculation of net loss per share:
Stock options to purchase common stock	14,987,043		11,687,959		14,987,043	11,687,959
Unvested Restricted Stock Units [Member]
Anti-dilutive potential common stock equivalents excluded from the calculation of net loss per share:
Unvested restricted stock units	1,578,621		461,248		1,578,621	461,248
Shares Issuable under ESPP [Member]
Anti-dilutive potential common stock equivalents excluded from the calculation of net loss per share:
Anti-dilutive potential common stock equivalents excluded from the calculation of net income (loss) per share	250,002		28,687		250,002	28,687