6. Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Payroll and incentive compensation	$ 2,271	$ 2,208
Real estate taxes	401	371
Other accrued expenses	446	405
Total accrued expenses	$ 3,118	$ 2,984