Debt (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Line of Credit Facility [Line Items]
Revolving credit facility, restriction on cash and cash equivalents	$ 923,000		$ 923,000		$ 5,350,000
Short-term restricted cash and securities	923,000		923,000		5,350,000
Total interest expense	65,000	55,000	110,000	159,000
GE Credit Agreement [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, aggregate amount	20,000,000		20,000,000
Term loan available upon request, aggregate amount	25,000,000		25,000,000
Revolving credit facility, restriction on cash and cash equivalents					5,000,000
Short-term restricted cash and securities					5,000,000
Revolving credit facility, expiration date			Sep. 26, 2019
Increase in applicable interest rate, per annum, if default occurs			2.00%
Revolving credit facility, outstanding balance	0		0		0
Revolving credit facility, aggregate interest rate	4.75%		4.75%		6.50%
Revolving credit facility, remaining availability	20,000,000		20,000,000		20,000,000
Minimum [Member] | GE Credit Agreement [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, restriction on cash and cash equivalents	5,000,000		5,000,000
Short-term restricted cash and securities	5,000,000		5,000,000
Revolving credit facility, liquidity requirement after effect to stock repurchase			$ 20,000,000