Stock-Based Compensation - Summary of Options Outstanding and Vested Under Stock Plans by Exercise Price (Detail)	12 Months Ended
	Dec. 31, 2020 $ / shares shares
$1.44 — $18.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price Lower Range Limit	$ 1.44
Options Outstanding, Exercise Price Upper Range Limit	$ 18.00
Number of Options Outstanding | shares	246,478
Options Outstanding, Weighted Average Remaining Contractual Life (in Years)	5 years 4 months 6 days
Options Outstanding, Weighted Average Exercise Price	$ 29.61
Options Vested, Number Exercisable | shares	180,476
Options Vested, Weighted Average Exercise Price	$ 25.24
$32.51 — $48.44 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price Lower Range Limit	32.51
Options Outstanding, Exercise Price Upper Range Limit	$ 48.44
Number of Options Outstanding | shares	234,728
Options Outstanding, Weighted Average Remaining Contractual Life (in Years)	5 years 11 months 8 days
Options Outstanding, Weighted Average Exercise Price	$ 54.28
Options Vested, Number Exercisable | shares	183,764
Options Vested, Weighted Average Exercise Price	$ 55.41
$49.94 — $63.23 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price Lower Range Limit	49.94
Options Outstanding, Exercise Price Upper Range Limit	$ 63.23
Number of Options Outstanding | shares	170,630
Options Outstanding, Weighted Average Remaining Contractual Life (in Years)	7 years 9 months 21 days
Options Outstanding, Weighted Average Exercise Price	$ 65.12
Options Vested, Number Exercisable | shares	75,867
Options Vested, Weighted Average Exercise Price	$ 65.44
$63.39 — $76.81 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price Lower Range Limit	63.39
Options Outstanding, Exercise Price Upper Range Limit	$ 76.81
Number of Options Outstanding | shares	141,314
Options Outstanding, Weighted Average Remaining Contractual Life (in Years)	4 years 7 months 9 days
Options Outstanding, Weighted Average Exercise Price	$ 80.46
Options Vested, Number Exercisable | shares	120,444
Options Vested, Weighted Average Exercise Price	$ 80.96
$84.30 — $97.52 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price Lower Range Limit	84.30
Options Outstanding, Exercise Price Upper Range Limit	$ 97.52
Number of Options Outstanding | shares	20,000
Options Outstanding, Weighted Average Remaining Contractual Life (in Years)	5 years 7 months 13 days
Options Outstanding, Weighted Average Exercise Price	$ 97.52
Options Vested, Number Exercisable | shares	20,000
Options Vested, Weighted Average Exercise Price	$ 97.52
$1.44 — $97.52 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price Lower Range Limit	1.44
Options Outstanding, Exercise Price Upper Range Limit	$ 97.52
Number of Options Outstanding | shares	813,150
Options Outstanding, Weighted Average Remaining Contractual Life (in Years)	5 years 11 months 1 day
Options Outstanding, Weighted Average Exercise Price	$ 54.69
Options Vested, Number Exercisable | shares	580,551
Options Vested, Weighted Average Exercise Price	$ 54.10