Stock-based Compensation - Schedule of Stock Options Activity (Detail) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($) $ / shares shares
NUMBER OF SHARES
Options outstanding at December 31, 2015 (shares) | shares	4,583,586
Granted (shares) | shares	783,936
Exercised (shares) | shares	(134,481)
Canceled (shares) | shares	(81,017)
Options outstanding at September 30, 2016 (shares) | shares	5,152,024
Options vested or expected to vest (shares) | shares	5,090,131
Options exercisable at September 30, 2016 (shares) | shares	2,973,566
WEIGHTED AVERAGE EXERCISE PRICE
Options outstanding at December 31, 2015 (in USD per share) | $ / shares	$ 12.86
Granted (in USD per share) | $ / shares	16.22
Exercised (in USD per share) | $ / shares	3.59
Cancelled (in USD per share) | $ / shares	19.22
Options outstanding at September 30, 2016 (in USD per share) | $ / shares	13.51
Options vested or expected to vest at (in USD per share) | $ / shares	13.44
Options exercisable at September 30, 2016 (in USD per share) | $ / shares	$ 10.19
WEIGHTED AVERAGE REMAINING CONTRACTUAL LIFE (YEARS)
Options outstanding, weighted average remaining contractual life (in years)	7 years 7 months 6 days
Options vested or expected to vest at (in years)	7 years 7 months 6 days
Options exercisable at September 30, 2016 (in years)	7 years
AGGREGATE INTRINSIC VALUE
Options outstanding | $	$ 124,827
Options vested and expected to vest at September 30, 2016 | $	123,667
Options exercisable at September 30, 2016 | $	$ 81,920