5. Income Taxes (Details - Reconciliation) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Income tax expense at the statutory federal income tax rate	$ 14,304	$ 14,707	$ 13,743
Increase (decrease) resulting from:
State income taxes	882	934	770
Section 199 manufacturing deduction	(1,383)	(1,290)	(1,307)
R&D tax credits	(2,254)	(393)	(626)
Other, net	396	255	103
Total income tax expense	$ 11,945	$ 14,213	$ 12,683