Stock-based Compensation - Schedule of Stock Options Activity (Detail) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) $ / shares shares
NUMBER OF SHARES
Options outstanding at December 31, 2015 | shares	4,583,586
Granted | shares	672,636
Exercised | shares	(25,121)
Canceled | shares	(29,682)
Options outstanding at March 31, 2016 | shares	5,201,419
Options vested and expected to vest at March 31, 2016 | shares	5,110,809
Options exercisable at March 31, 2016 | shares	2,500,586
WEIGHTED AVERAGE EXERCISE PRICE
Options outstanding at December 31, 2015 (in USD per share) | $ / shares	$ 12.86
Granted (in USD per share) | $ / shares	15.85
Exercised (in USD per share) | $ / shares	2.61
Cancelled (in USD per share) | $ / shares	22.57
Options outstanding at March 31, 2016 (in USD per share) | $ / shares	13.24
Options vested and expected to vest at March 31, 2016 (in USD per share) | $ / shares	13.14
Options exercisable at March 31, 2016 (in USD per share) | $ / shares	$ 9.02
WEIGHTED AVERAGE REMAINING CONTRACTUAL LIFE (YEARS)
Options outstanding, weighted average remaining contractual life	7 years 11 months 27 days
Options vested and expected to vest at March 31, 2016	7 years 11 months 23 days
Options exercisable at March 31, 2016	7 years 2 months
AGGREGATE INTRINSIC VALUE
Options outstanding | $	$ 21,177
Options vested and expected to vest at March 31, 2016 | $	21,096
Options exercisable at March 31, 2016 | $	$ 16,299