Summary of Restricted Stock Unit Activity (Detail) - Restricted Stock Units (RSUs) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) shares
Options Outstanding
Unvested at December 31, 2018	705,413
Awarded	328,812
Vested	(251,776)
Forfeited/expired/cancelled	(47,465)
Unvested at December 31, 2019	734,984
Vested and expected to vest at December 31, 2019	675,618	[1]
Weighted-Average Remaining Contractual Term (in years)
Unvested at December 31, 2019	3 years 9 months 21 days
Vested and expected to vest at December 31, 2019	3 years 4 months 2 days	[1]
Aggregate Intrinsic Value
Unvested at December 31, 2019 | $	$ 67,986
Vested and expected to vest at December 31, 2019 | $	$ 62,495	[1]

[1] Represents the number of vested stock units as of December 31, 2019 plus the number of unvested stock units expected to vest as of December 31, 2019 based on the unvested outstanding stock units at December 31, 2019 adjusted for estimated forfeiture rates of 8% for awards granted to non-executive level employees and 3% for awards granted to executive level employees.