Equity (Exercise Price Ranges) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of outstanding options (in shares)	15,375,960
Outstanding Options, weighted average remaining contractual term	7 years 8 months 12 days
Outstanding Options, weighted average exercise price (in dollars per share)	$ 2.46
Number of exercisable options (in shares)	6,807,732
Exercisable Options, weighted average exercise price (in dollars per share)	$ 1.33
$0.50 - $0.76
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, lower range limit (in dollars per share)	$ 0.50
Exercise Price Range, upper range limit (in dollars per share)	$ 0.76
Number of outstanding options (in shares)	1,225,935
Outstanding Options, weighted average remaining contractual term	4 years
Outstanding Options, weighted average exercise price (in dollars per share)	$ 0.65
Number of exercisable options (in shares)	1,225,935
Exercisable Options, weighted average exercise price (in dollars per share)	$ 0.65
$0.87 - $1.35
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, lower range limit (in dollars per share)	$ 0.87
Exercise Price Range, upper range limit (in dollars per share)	$ 1.35
Number of outstanding options (in shares)	6,570,341
Outstanding Options, weighted average remaining contractual term	7 years 7 months 6 days
Outstanding Options, weighted average exercise price (in dollars per share)	$ 1.20
Number of exercisable options (in shares)	3,604,469
Exercisable Options, weighted average exercise price (in dollars per share)	$ 1.18
$1.40 - $2.29
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, lower range limit (in dollars per share)	$ 1.40
Exercise Price Range, upper range limit (in dollars per share)	$ 2.29
Number of outstanding options (in shares)	1,571,700
Outstanding Options, weighted average remaining contractual term	6 years 1 month 6 days
Outstanding Options, weighted average exercise price (in dollars per share)	$ 1.66
Number of exercisable options (in shares)	1,321,698
Exercisable Options, weighted average exercise price (in dollars per share)	$ 1.66
$2.33 - $3.75
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, lower range limit (in dollars per share)	$ 2.33
Exercise Price Range, upper range limit (in dollars per share)	$ 3.75
Number of outstanding options (in shares)	2,091,984
Outstanding Options, weighted average remaining contractual term	8 years 8 months 12 days
Outstanding Options, weighted average exercise price (in dollars per share)	$ 2.77
Number of exercisable options (in shares)	655,630
Exercisable Options, weighted average exercise price (in dollars per share)	$ 2.77
$3.95 - $6.02
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, lower range limit (in dollars per share)	$ 3.95
Exercise Price Range, upper range limit (in dollars per share)	$ 6.02
Number of outstanding options (in shares)	3,435,500
Outstanding Options, weighted average remaining contractual term	9 years 3 months 18 days
Outstanding Options, weighted average exercise price (in dollars per share)	$ 5.13
Number of exercisable options (in shares)	0
Exercisable Options, weighted average exercise price (in dollars per share)	$ 0.00
$6.04 - $7.93
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, lower range limit (in dollars per share)	$ 6.04
Exercise Price Range, upper range limit (in dollars per share)	$ 7.93
Number of outstanding options (in shares)	480,500
Outstanding Options, weighted average remaining contractual term	8 years 10 months 24 days
Outstanding Options, weighted average exercise price (in dollars per share)	$ 6.61
Number of exercisable options (in shares)	0
Exercisable Options, weighted average exercise price (in dollars per share)	$ 0.00