Equity Activity of Stock Options (Details)	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares
Number of Shares
Outstanding, beginning of period (in shares) | shares	16,474,227
Granted (in shares) | shares	75,100
Exercised (in shares) | shares	(2,220,881)
Unvested options forfeited (in shares) | shares	(239,322)
Vested options expired (in shares) | shares	(69,495)
Outstanding, end of period (in shares) | shares	14,019,629
Vested at end of period (in shares) | shares	10,951,694
Exercisable options, vested and expected to vest (in shares) | shares	13,917,122	[1]
Weighted- Average Exercise Price
Outstanding, weighted average exercise price, beginning of period (in dollars per share) | $ / shares	$ 3.43
Granted, weighted average exercise price (in dollars per share) | $ / shares	9.66
Exercised, weighted average exercise price (in dollars per share) | $ / shares	2.08
Unvested options forfeited weighted-average exercise price (in dollars per share) | $ / shares	6.66
Vested options expired weighted-average exercise price (in dollars per share) | $ / shares	2.61
Outstanding, weighted average exercise price, end of period (in dollars per share) | $ / shares	3.62
Vested at end of period weighted average exercise price (in dollars per share) | $ / shares	2.80
Vested and expected to vest, weighted average exercise price (in dollars per share) | $ / shares	$ 3.60	[1]
Stock options, additional disclosures
Outstanding options, weighted average remaining contractual term	6 years 6 months
Vested at end of period weighted average remaining contractual term	6 years 2 months 12 days
Vested and expected to vest, weighted average remaining contractual term	6 years 6 months	[1]
Outstanding intrinsic value | $	$ 80,740,577
Vested at end of period aggregate intrinsic value | $	71,955,234
Vested and expected to vest, aggregate intrinsic value | $	$ 80,496,150	[1]

[1] Includes forfeiture adjusted unvested shares.