Annual report pursuant to Section 13 and 15(d)

Defined Contribution Plan (Details)

Defined Contribution Plan (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Defined Contribution Plan      
Company's matching contributions equal to each employee's contribution (as a percent) 50.00%us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent    
Maximum contribution of employees as a percentage of their compensation 6.00%us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent    
Amount expensed $ 194us-gaap_DefinedContributionPlanCostRecognized $ 182us-gaap_DefinedContributionPlanCostRecognized $ 166us-gaap_DefinedContributionPlanCostRecognized