(9) Income Taxes (Details - Tax rate effect) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Expense at federal tax rate	$ 4,225	$ 1,924	$ 3,928
State taxes, net of federal income tax effect	1,505	1,027	1,718
Stock-based compensation	35	169	238
Non-deductible expenses	974	856	824
Net operating loss carryback	(9,435)	0	0
Effect of change in tax rate	0	0	0
Accounting method change	0	0	(2,100)
Other	1,139	(220)	(767)
Income tax expense	$ (1,557)	$ 3,756	$ 3,841