Summary of Restricted Stock Unit Activity (Detail) - Restricted Stock Units (RSUs) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) shares
Options Outstanding
Restricted stock units outstanding at December 31, 2015	186,351
Granted	251,384
Exercised	(63,017)
Forfeited/cancelled	(20,880)
Restricted stock units outstanding at December 31, 2016	353,838
Restricted stock units exercisable at December 31, 2016	0
Vested and expected to vest at December 31, 2016	309,229	[1]
Weighted-Average Remaining Contractual Term (in years)
Restricted stock units outstanding at December 31, 2016	9 years 4 days
Restricted stock units exercisable at December 31, 2016	0 years
Vested and expected to vest at December 31, 2016	9 years 4 days	[1]
Aggregate Intrinsic Value
Restricted stock units outstanding at December 31, 2016 | $	$ 10,905
Restricted stock units exercisable at December 31, 2016 | $	0
Vested and expected to vest at December 31, 2016 | $	$ 9,530	[1]

[1] Represents the number of vested restricted stock units as of December 31, 2016 plus the number of unvested restricted stock units expected to vest as of December 31, 2016 based on the unvested outstanding restricted stock units at December 31, 2016 adjusted for estimated forfeiture rates of 8% for awards granted to non-executive level employees and 3% for awards granted to executive level employees.