Income Taxes - Temporary Differences (Details) - USD ($) $ in Thousands |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|---|---|---|---|
| Income Tax Disclosure [Abstract] | |||
| Allowance for doubtful accounts | $ 18 | $ 11 | $ 15 |
| Accrued expenses and other reserves | 2,244 | 2,082 | 1,960 |
| Tax credits, deferred R&D, and other | 122 | 44 | 87 |
| Net operating loss | 5,384 | 6,871 | 3,989 |
| Valuation allowance | (7,768) | (9,008) | (6,051) |
| Net deferred tax assets | $ 0 | $ 0 | $ 0 |