Accounting for Shared-Based Payments (Details 2) (USD $)	3 Months Ended	12 Months Ended						28 Months Ended	12 Months Ended	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Mar. 31, 2014 Stock options Contingent vesting	Dec. 31, 2013 Stock options Exercise price per Share 0.44 - 20.01	Mar. 31, 2014 Stock options Exercise price per share 5.97	Mar. 31, 2014 Stock options Exercise price per share 3.40 - 3.95	Mar. 31, 2014 Stock options Exercise price per share 20.01	Mar. 31, 2014 Stock options Exercise price per share 0.44 - 17.79
Number of Options
Granted (in shares)										350,000
Exercised (in shares)											(9,999)
Forfeited (in shares)												(17,990)
Balance outstanding, end of period (in shares)									11,324,049				11,646,060
Exercisable at the end of the period (in shares)													5,157,125
Exercise Price Per Share
Exercise price, low end of the range (in dollars per share)									$ 0.44		$ 3.40		$ 0.44
Exercise price, high end of the range (in dollars per share)									$ 20.01	$ 5.97	$ 3.95	$ 20.01	$ 17.79
Weighted Average Exercise Price Per Share
Granted (in dollars per share)										$ 5.97
Exercised (in dollars per share)											$ 3.58
Forfeited (in dollars per share)												$ 20.01
Balance outstanding, end of period (in dollars per share)									$ 3.31				$ 3.37
Exercisable at the end of the period (in dollars per share)													$ 2.98
Intrinsic Value
Intrinsic value of options outstanding (in dollars)									$ 37,521,000				$ 39,215,000
Intrinsic value of options exercisable (in dollars)													15,367,000
Weighted Average Remaining Contractual Term
Balance at the end of the period									6 years 11 months 8 days				6 years 9 months 18 days
Exercisable at the end of the period													5 years 10 months 20 days
Grant date fair value (in dollars)								28,918,822
Stock based compensation expense (in dollars)	$ 1,264,000	$ 4,489,000	$ 2,297,000	$ 481,000	$ 694,000	$ 1,052,000	$ 380,000	$ 0