Accounting for Shared-Based Payments (Details 2) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended	9 Months Ended				69 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013 Stock options Exercise price per Share 0.44 - 20.01	Sep. 30, 2014 Stock options Exercise price per share 4.24 - 5.97	Sep. 30, 2014 Stock options Exercise price per share 3.40 - 3.95	Sep. 30, 2014 Stock options Exercise price per share 8.34 - 20.01	Sep. 30, 2014 Stock options Exercise price per share 0.44 - 13.90	Sep. 30, 2014 Stock options Exercise price per share 0.44 - 13.90 Contingent vesting
Number of Options
Granted (in shares)						1,664,000
Exercised (in shares)							(9,999)
Forfeited (in shares)								(110,190)
Balance outstanding, end of period (in shares)					11,324,049				12,867,860	4,364,000
Exercisable at the end of the period (in shares)									5,880,483
Exercise Price Per Share
Exercise price, low end of the range (in dollars per share)					$ 0.44	$ 3.70	$ 3.40	$ 8.34	$ 0.44
Exercise price, high end of the range (in dollars per share)					$ 20.01	$ 5.97	$ 3.95	$ 20.01	$ 13.90
Weighted Average Exercise Price Per Share
Granted (in dollars per share)						$ 4.63
Exercised (in dollars per share)							$ 3.58
Forfeited (in dollars per share)								$ 17.51
Balance outstanding, end of period (in dollars per share)					$ 3.31				$ 3.36	$ 0.70
Exercisable at the end of the period (in dollars per share)									$ 2.96
Intrinsic Value
Intrinsic value of options outstanding (in dollars)					$ 37,521,000				$ 7,555,000
Intrinsic value of options exercised (in dollars)							23,000
Intrinsic value of options exercisable (in dollars)									4,552,000
Weighted Average Remaining Contractual Term
Balance at the end of the period					6 years 11 months 9 days				6 years 8 months 9 days
Exercisable at the end of the period									5 years 10 months 28 days
Additional disclosures
Total stock-based compensation expense (in dollars)	$ 922,000	$ 1,090,000	$ 3,187,000	$ 3,258,000						$ 0