Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Dec. 31, 2018	May 31, 2017	Nov. 30, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	16,700			186,200
Incremental Common Shares Attributable to Share-based Payment Arrangements, Total		2,217			3,553
Stock Repurchase Program, Authorized Amount	$ 250,000			$ 250,000
Stock Repurchased During Period, Shares	1,245			32,985
Stock Repurchased During Period, Value	$ 4,000	$ 42,000		$ 130,000	$ 228,000
Letters of Credit Outstanding, Amount	0			0
Accounts Receivable, Allowance for Credit Loss, Current	323,000			323,000			$ 222,000
Amortization of Intangible Assets, Total	55,000			164,000
Impairment of Long-Lived Assets to be Disposed of	0	0		0	0
Operating Lease, Right-of-Use Asset	5,018,000			5,018,000		$ 5,731,000
Operating Lease, Liability, Total	5,358,000			5,358,000		$ 5,731,000
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Expense	35,000	35,000		110,000	80,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total	403,000			$ 403,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition				3 years 47 days
Stock Appreciation Rights (SARs) [Member]
Share-based Payment Arrangement, Expense	$ 0	$ 0		$ 0	$ 0
Restricted Stock [Member]
Share-based Payment Arrangement, Expense				$ 116,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period				25,000
Stock Incentive Plan 2017 [Member] | Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized								350,000
Equity Appreciation Rights Plan 2010 [Member] | Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized									1,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted			0	100,000	0