Income Taxes - Schedule of Provision for Income Tax Expense (Details) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Current:      
U.S. Federal $ 0 $ 0 $ 0
State 1 1 1
Foreign 16 50 42
Total current 17 51 43
Deferred:      
U.S. Federal 0 0 0
State 0 0 0
Foreign 0 0 0
Total deferred 0 0 0
Provision for income taxes $ 17 $ 51 $ 43