Stock-based Compensation - Schedule of Stock Options Activity (Detail) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($) $ / shares shares
NUMBER OF SHARES
Options outstanding at December 31, 2015 | shares	4,583,586
Granted | shares	758,736
Exercised | shares	(30,403)
Canceled | shares	(40,640)
Options outstanding at June 30, 2016 | shares	5,271,279
Options vested and expected to vest at June 30, 2016 | shares	5,194,864
Options exercisable at June 30, 2016 | shares	2,760,266
WEIGHTED AVERAGE EXERCISE PRICE
Options outstanding at December 31, 2015 (in USD per share) | $ / shares	$ 12.86
Granted (in USD per share) | $ / shares	16.18
Exercised (in USD per share) | $ / shares	2.44
Cancelled (in USD per share) | $ / shares	21.96
Options outstanding at June 30, 2016 (in USD per share) | $ / shares	11.04
Options vested and expected to vest at June 30, 2016 (in USD per share) | $ / shares	13.25
Options exercisable at June 30, 2016 (in USD per share) | $ / shares	$ 9.48
WEIGHTED AVERAGE REMAINING CONTRACTUAL LIFE (YEARS)
Options outstanding, weighted average remaining contractual life	7 years 9 months
Options vested and expected to vest at June 30, 2016	7 years 9 months
Options exercisable at June 30, 2016	7 years
AGGREGATE INTRINSIC VALUE
Options outstanding | $	$ 35,051
Options vested and expected to vest at June 30, 2016 | $	34,896
Options exercisable at June 30, 2016 | $	$ 27,204