9. Retirement savings plan

12 Months Ended

Dec. 31, 2014

Disclosure Text Block Supplement [Abstract]

Compensation and Employee Benefit Plans [Text Block]

9. Retirement savings plan

We maintain a 401(k) plan under which all full-time employees are eligible to participate at the beginning of each month immediately following their date of hire.  We match employees’ contributions at a rate of 50% of employees’ contributions up to the first 6% of the employees’ compensation contributed to the 401(k) plan.  Our matching contributions were $282,000, $265,000 and $280,000 in 2014, 2013 and 2012, respectively.