7. Stockholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Common Stock
Beginning balance, shares	13,943,820	13,929,381	13,929,381	13,922,290	13,883,937	13,882,937	13,929,381	13,882,937
Beginning balance, amount	$ 8,366	$ 8,357	$ 8,357	$ 8,353	$ 8,330	$ 8,330	$ 8,357	$ 8,330
Restricted stock units issued, shares	18,546			7,091	38,353
Restricted stock units issued, amount	$ 11			$ 4	$ 23
Common stock issued under restricted stock units, shares		14,439
Common stock issued under restricted stock units, amount		$ 9
Stock options exercised and issued, shares						1,000
Stock options exercised and issued, amount						$ 0
Ending balance, shares	13,962,366	13,943,820	13,929,381	13,929,381	13,922,290	13,883,937	13,962,366	13,929,381
Ending balance, amount	$ 8,377	$ 8,366	$ 8,357	$ 8,357	$ 8,353	$ 8,330	$ 8,377	$ 8,357
Additional Paid-In Capital
Beginning balance, amount	26,235	26,146	26,095	25,988	25,941	25,867	26,095	25,867
Restricted stock units issued, amount	(11)			(4)	(23)
Common stock issued under restricted stock units, amount		(9)
Stock options exercised and issued, amount						2
Share-based compensation expense-stock options	34	30	30	42	37	31
Share-based compensation expense-restricted stock units	23	68	21	11	33	41
Ending balance, amount	26,281	26,235	26,146	26,037	25,988	25,941	26,281	26,037
Accumulated Deficit
Beginning balance, amount	(8,039)	(7,485)	(6,043)	(4,467)	(3,965)	(2,393)	(6,043)	(2,393)
Dividends declared ($0.02 per share)	(250)	(252)	(250)	(253)	(255)	(254)
Net loss		(302)	(1,192)	238	(247)	(1,318)
Ending balance, amount	(7,611)	(8,039)	(7,485)	(4,482)	(4,467)	(3,965)	(7,611)	(4,482)
Treasury Stock
Beginning balance, amount	(5,402)	(5,376)	(5,133)	(4,642)	(4,429)	(4,092)	(5,133)	(4,092)
Net loss	678
Repurchase of common stock		(26)	(243)	(253)	(213)	(337)
Ending balance, amount	(5,402)	(5,402)	(5,376)	(4,895)	(4,642)	(4,429)	(5,402)	(4,895)
Beginning balance, amount	21,160	21,642	23,276	25,232	25,877	27,712	23,276	27,712
Restricted stock units issued, amount	0			0	0
Common stock issued under restricted stock units, amount		0
Stock options exercised and issued, amount						2
Share-based compensation expense-stock options	34	30	30	42	37	31
Share-based compensation expense-restricted stock units	23	68	21	11	33	41	112	85
Dividends declared ($0.02 per share)	(250)	(252)	(250)	(253)	(255)	(254)
Net loss	678	(302)	(1,192)	238	(247)	(1,318)	(817)	(1,327)
Repurchase of common stock		(26)	(243)	(253)	(213)	(337)	(269)	(803)
Ending balance, amount	$ 21,645	$ 21,160	$ 21,642	$ 25,017	$ 25,232	$ 25,877	$ 21,645	$ 25,017