Stock-Based Compensation - Summary of Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock options, Outstanding, balance	11,408,000
Stock options, Granted	3,806,000
Stock options, Exercised	(1,210,000)
Stock options, Cancelled/Forfeited	(1,209,000)
Stock options, Outstanding, Balance	12,795,000	11,408,000
Stock options, Options vested and exercisable	6,409,000
Stock options, Options vested and expected to vest	10,460,000
Weighted-average exercise price, Outstanding, Balance	$ 4.42
Weighted-average exercise price, Granted	9.50
Weighted-average exercise price, Exercised	2.96
Weighted-average exercise price, Cancelled/Forfeited	6.27
Weighted-average exercise price, Outstanding, Balance	5.89	$ 4.42
Weighted-average exercise price, Options vested and exercisable	3.88
Weighted-average exercise price, Options vested and expected to vest	$ 5.69
Weighted-average remaining contractual life, options outstanding	7 years 9 months 26 days	8 years 2 months 12 days
Weighted-average remaining contractual life, options vested and exercisable	6 years 9 months 18 days
Weighted-average remaining contractual life, options vested and expected to vest	7 years 7 months 24 days