Stock-based Compensation - Schedule of Stock Options Activity (Detail) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares
NUMBER OF SHARES
Beginning balance (in shares) | shares	5,255,930
Granted (in shares) | shares	988,459
Exercised (in shares) | shares	(198,735)
Canceled (in shares) | shares	(17,571)
Ending balance (in shares) | shares	6,028,083
Options exercisable (in shares) | shares	3,692,130
WEIGHTED AVERAGE EXERCISE PRICE
Beginning balance (in dollars per share) | $ / shares	$ 14.34
Granted (in dollars per share) | $ / shares	44.63
Exercised (in dollars per share) | $ / shares	10.93
Cancelled (in dollars per share) | $ / shares	34.34
Ending balance (in dollars per share) | $ / shares	19.36
Options exercisable (in dollars per share) | $ / shares	$ 11.85
WEIGHTED AVERAGE REMAINING CONTRACTUAL LIFE (YEARS)
Options outstanding, weighted average remaining contractual life (in years)	7 years 4 months 29 days
Options exercisable (in years)	6 years 6 months 16 days
AGGREGATE INTRINSIC VALUE
Options outstanding | $	$ 200,150
Options exercisable | $	$ 150,268