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Summary of Significant Accounting Policies (Narrative) (Details) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2015 USD ($) | Sep. 30, 2015 USD ($) | Jun. 30, 2015 USD ($) | Mar. 31, 2015 USD ($) | Dec. 31, 2014 USD ($) | Sep. 30, 2014 USD ($) | Jun. 30, 2014 USD ($) | Mar. 31, 2014 USD ($) | Dec. 31, 2015 USD ($) segment | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($)
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Cash equivalents, qualification, maximum original maturity of short-term investments |  |  |  |  |  |  |  |  | 3 months |  |
Customer deposit requirements, large custom contracts, maximum percentage |  |  |  |  |  |  |  |  | 50.00% |  |
Allowance for doubtful accounts | $ 833,000 |  |  |  | $ 507,000 |  |  |  | $ 833,000 | $ 507,000 |
Total revenue | 25,755,000 | $ 21,193,000 | $ 24,230,000 | $ 24,741,000 | 27,101,000 | $ 25,599,000 | $ 21,952,000 | $ 22,322,000 | 95,919,000 | 96,974,000 | $ 89,248,000
Impairment of goodwill |  |  |  |  |  |  |  |  | 0 | 0 |
Product warranty reserves | 103,000 |  |  |  | 0 |  |  |  | 103,000 | 0 |
Uncertain tax positions | $ 0 |  |  |  | $ 0 |  |  |  | $ 0 | $ 0 |
Number of business segments | segment |  |  |  |  |  |  |  |  | 1 |  |
Bill and Hold Arrangement |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total revenue |  |  |  |  |  |  |  |  | $ 4,000,000 |  |

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