Equity-Based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended			12 Months Ended		1 Months Ended					12 Months Ended	1 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended
	Dec. 31, 2013 item	Dec. 31, 2013 Stock options	Dec. 31, 2012 Stock options	Dec. 31, 2013 Restricted stock units	Dec. 31, 2012 Restricted stock units	Feb. 28, 2013 Restricted stock units Senior management	Feb. 28, 2013 Restricted stock units Senior management Maximum	May 31, 2013 2007 Equity Incentive Plan	May 31, 2010 2007 Equity Incentive Plan	May 31, 2009 2007 Equity Incentive Plan	Dec. 31, 2013 2007 Equity Incentive Plan	May 31, 2009 2007 Equity Incentive Plan Stock options	Dec. 31, 2013 2007 Equity Incentive Plan Stock options Minimum	Dec. 31, 2013 2007 Equity Incentive Plan Stock options Maximum	May 31, 2009 2007 Equity Incentive Plan Restricted stock units	Dec. 31, 2013 2007 Equity Incentive Plan Restricted stock units	Dec. 31, 2013 2000 Stock Plan	Dec. 31, 2013 2000 Stock Plan Stock options	Dec. 31, 2013 Other Equity Compensation Grants Stock options Senior management	Dec. 31, 2012 Other Equity Compensation Grants Stock options Senior management	Dec. 31, 2013 Other Equity Compensation Grants Restricted stock units Senior management	Dec. 31, 2012 Other Equity Compensation Grants Restricted stock units Senior management
Equity-Based Compensation
Number of equity compensation plans	2
Equity compensation plans
Shares authorized for issuance								1,100,000	800,000	600,000
Reduction in number of shares available for issuance												1			1.5
Award vesting period						3 years										4 years			4 years	4 years	4 years	4 years
Number of options and restricted stock units granted since inception (in shares)											6,289,350						2,182,700
Number of stock options expired or terminated since inception (in shares)											2,558,113						984,339
Number of restricted stock units forfeited since inception (in shares)											626,348						1,500
Stock options exercised since inception (in shares)											139,146						1,049,420
Shares of common stock issued pursuant to vested restricted stock units since inception											475,614						42,500
Number of stock options outstanding (in shares)		2,819,676	2,190,073								2,199,735						104,941
Number of restricted stock units outstanding (in shares)				465,394	373,676						290,394						0
Remaining number of shares available for future grants											2,024,621						0
Expiration term													7 years	10 years				10 years
Granted (in shares)		1,120,050																	270,000	300,000
Forfeited (in shares)		(366,789)																	(45,000)
Granted (in shares)				270,525		82,500															115,000	100,000
Forfeited (in shares)				(25,918)																	(15,000)
Fair value of awards issued							$ 0.7
Expense recognition period		2 years 8 months 12 days		2 years 1 month 6 days		3 years