| Quarterly Financial Information [Text Block] |
| | Quarterly Financial Information (unaudited) | Summarized quarterly financial data is as follows (in thousands, except per share data): | 2016 | | Q1 | | Q2 | | Q3 | | Q4 | | Net sales | | $ | 34,503 | | | $ | 37,902 | | | $ | 37,220 | | | $ | 36,507 | | | Gross profit | | | 7,727 | | | | 10,295 | | | | 8,452 | | | | 8,176 | | | Net income | | | 1,075 | | | | 2,735 | | | | 2,669 | | | | 1,491 | | | Basic net income per share | | | 0.15 | | | | 0.38 | | | | 0.37 | | | | 0.21 | | | Diluted net income per share | | | 0.15 | | | | 0.38 | | | | 0.37 | | | | 0.20 | | | 2015 | | Q1 | | Q2 | | Q3 | | Q4 | | Net sales | | $ | 33,977 | | | $ | 36,499 | | | $ | 34,441 | | | $ | 33,933 | | | Gross profit | | | 8,638 | | | | 10,293 | | | | 9,510 | | | | 9,013 | | | Net income | | | 1,653 | | | | 2,272 | | | | 1,992 | | | | 1,676 | | | Basic net income per share | | | 0.23 | | | | 0.32 | | | | 0.28 | | | | 0.24 | | | Diluted net income per share | | | 0.23 | | | | 0.32 | | | | 0.28 | | | | 0.23 | |
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