Income Taxes (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Income Taxes
Income tax expense	$ 88,000	$ 55,000	$ 163,000	$ 108,000
Unrecognized tax benefits	$ 2,200,000		$ 2,200,000		$ 2,200,000