Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2017	8,777,988
Balance at Dec. 31, 2017	$ 88	$ 14,877	$ (143)	$ 4,631	$ 19,453
Net income				893	893
Stock compensation expense		13			13
Foreign currency translation adjustment			1		1
Unrealized loss on marketable securities			(17)		(17)
Balance (in shares) at Mar. 31, 2018	8,777,988
Balance at Mar. 31, 2018	$ 88	14,890	(159)	5,524	20,343
Balance (in shares) at Dec. 31, 2017	8,777,988
Balance at Dec. 31, 2017	$ 88	14,877	(143)	4,631	19,453
Net income					1,951
Unrealized loss on marketable securities					(12)
Balance (in shares) at Jun. 30, 2018	8,797,988
Balance at Jun. 30, 2018	$ 88	14,937	(140)	6,582	21,467
Balance (in shares) at Mar. 31, 2018	8,777,988
Balance at Mar. 31, 2018	$ 88	14,890	(159)	5,524	20,343
Net income				1,058	1,058
Stock compensation expense		13			13
Foreign currency translation adjustment			14		14
Unrealized loss on marketable securities			5		5
Stock options exercised (in shares)	20,000
Stock options exercised		34			34
Balance (in shares) at Jun. 30, 2018	8,797,988
Balance at Jun. 30, 2018	$ 88	14,937	(140)	6,582	$ 21,467
Balance (in shares) at Dec. 31, 2018	8,817,988				8,817,988
Balance at Dec. 31, 2018	$ 88	15,050	(92)	10,875	$ 25,921
Net income				2,072	2,072
Stock compensation expense		25			25
Foreign currency translation adjustment			(1)		(1)
Stock options exercised (in shares)	33,000
Stock options exercised	$ 1	58			59
Balance (in shares) at Mar. 31, 2019	8,850,988
Balance at Mar. 31, 2019	$ 89	15,133	(93)	12,947	$ 28,076
Balance (in shares) at Dec. 31, 2018	8,817,988				8,817,988
Balance at Dec. 31, 2018	$ 88	15,050	(92)	10,875	$ 25,921
Net income					4,180
Unrealized loss on marketable securities
Stock options exercised (in shares)					33,000
Balance (in shares) at Jun. 30, 2019	8,850,988				8,850,988
Balance at Jun. 30, 2019	$ 89	15,188	(128)	15,055	$ 30,204
Balance (in shares) at Mar. 31, 2019	8,850,988
Balance at Mar. 31, 2019	$ 89	15,133	(93)	12,947	28,076
Net income				2,108	2,108
Stock compensation expense		55			55
Foreign currency translation adjustment			(35)		(35)
Unrealized loss on marketable securities
Stock options exercised (in shares)					0
Balance (in shares) at Jun. 30, 2019	8,850,988				8,850,988
Balance at Jun. 30, 2019	$ 89	$ 15,188	$ (128)	$ 15,055	$ 30,204