Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Revenues	$ 36,215	$ 38,324
Cost of goods sold	18,650	19,800
Gross profit	17,565	18,524
Operating expenses:
Selling	1,735	1,520
General and administrative	3,949	3,958
Research and development	1,416	1,560
Operating Expenses, Total	7,100	7,038
Operating income	10,465	11,486
Interest income	123	177
Other income (expense), net	(345)	0
Nonoperating Income	(222)	177
Income before provision for income taxes	10,243	11,663
Provision for income taxes	(3,298)	(4,061)
Net income	$ 6,945	$ 7,602
Net income per basic share	$ 3.81	$ 4.05
Weighted average basic shares outstanding	1,823	1,875
Net income per diluted share	$ 3.76	$ 4.01
Weighted average diluted shares outstanding	1,849	1,895
Dividends per common share	$ 0.9	$ 0.75