Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income:
Interest and fees on loans		$ 44,955	$ 39,112	$ 35,435
Interest on taxable securities		5,165	3,921	2,986
Interest on tax-exempt securities		1,629	2,144	2,256
Interest on interest-bearing deposits in other banks		952	772	332
Total interest income		52,701	45,949	41,009
Interest expense:
Interest on demand - interest-bearing		414	274	201
Interest on money market accounts		646	470	322
Interest on savings accounts		288	200	174
Interest on certificates of deposit		1,910	2,188	2,179
Interest on Federal Home Loan Bank of San Francisco borrowings		435	3	484
Interest on other borrowings		1,077	1,165	1,183
Interest on junior subordinated debentures		385	287	235
Total interest expense		5,155	4,587	4,778
Net interest income		47,546	41,362	36,231
Provision for loan and lease losses			950
Net interest income after provision for loan and lease losses		47,546	40,412	36,231
Noninterest income:
Fees on payroll and benefit processing		652	658	593
Life insurance		512	1,050	613
Gains on sale of investment securities, net		44	137	244
Impairment losses on investment securities		0	0	(546)
Federal Home Loan Bank of San Francisco dividends		480	318	644
Gain (loss) on sale of OREO		73	368	(109)
Insured cash sweep fees			197	3
Other income		445	461	636
Total noninterest income		4,019	4,824	3,486
Noninterest expense:
Salaries and related benefits		18,709	17,819	16,425
Premises and equipment		4,047	4,242	3,869
Federal Deposit Insurance Corporation insurance premium		376	318	615
Data processing fees		1,933	1,749	1,675
Professional service fees		1,431	1,398	1,690
Telecommunications		594	879	751
Acquisition costs		844		580
Loss on cancellation of interest rate swap				2,325
Other expenses		4,272	4,559	4,570
Total noninterest expense		32,206	30,964	32,500
Income before provision for income taxes		19,359	14,272	7,217
Provision for income taxes		3,629	6,928	1,958
Net income		$ 15,730	$ 7,344	$ 5,259
Earnings per share - basic (in dollars per share)		$ 0.97	$ 0.48	$ 0.39
Weighted average shares - basic (in shares)	[1]	16,248	15,207	13,367
Earnings per share - diluted (in dollars per share)		$ 0.96	$ 0.48	$ 0.39
Weighted average shares - diluted (in shares)		16,332	15,310	13,425
Deposit Account [Member]
Noninterest income:
Revenue from Contract with Customer		$ 682	$ 542	$ 413
Credit and Debit Card [Member]
Noninterest income:
Revenue from Contract with Customer		$ 1,131	$ 1,093	$ 995

[1] Excludes unvested restricted shares because they do not have dividend or voting rights.