Stock Option and Compensation Plans (Details 3) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Option and Compensation Plans
Share-based compensation expense	$ 2,871,000	$ 640,000	$ 248,000
Stock options
Stock Option and Compensation Plans
Share-based compensation expense	2,200,000	500,000	200,000
Unrecognized share-based compensation costs, net of estimated forfeitures	14,600,000
Expected weighted average period to recognize share-based compensation costs	3 years 3 months 18 days
Non-employee Options | Consultants
Stock Option and Compensation Plans
Share-based compensation expense	700,000	100,000	100,000
Unrecognized share-based compensation costs, net of estimated forfeitures	$ 1,900,000
Expected weighted average period to recognize share-based compensation costs	3 years