Equity (Activity of Stock Options) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013
Number of Shares
Outstanding, beginning of period (in shares)	13,614,135
Granted (in shares)	4,021,000
Exercised (in shares)	(1,958,674)
Unvested options forfeited (in shares)	(265,002)
Vested options expired (in shares)	(35,499)
Outstanding, end of period (in shares)	15,375,960
Vested at end of period (in shares)	6,807,732
Exercisable options, vested and expected to vest (in shares)	15,081,653	[1]
Weighted- Average Exercise Price
Outstanding, weighted average exercise price, beginning of period (in dollars per share)	$ 1.42
Granted, weighted average exercise price (in dollars per share)	$ 5.31
Exercised, weighted average exercise price (in dollars per share)	$ 1.01
Unvested options forfeited weighted-average exercise price (in dollars per share)	$ 3.47
Vested options expired weighted-average exercise price (in dollars per share)	$ 1.11
Outstanding, weighted average exercise price, end of period (in dollars per share)	$ 2.46
Vested at end of period weighted average exercise price (in dollars per share)	$ 1.33
Vested and expected to vest, weighted average exercise price (in dollars per share)	$ 2.42	[1]
Stock options, additional disclosures
Outstanding Options, weighted average remaining contractual term	7 years 8 months 12 days
Vested at end of period weighted average remaining contractual term	6 years 6 months
Vested and expected to vest, weighted average remaining contractual term	7 years 8 months 12 days	[1]
Outstanding intrinsic value	$ 96,614,260
Vested at end of period aggregate intrinsic value	50,441,475
Vested and expected to vest, aggregate intrinsic value	$ 95,324,825	[1]

[1] Includes forfeiture adjusted unvested shares.