| December 31 , 201 7 | December 31, 201 6 | |||||||
| Current: | ||||||||
| Federal (Net of a net operating loss benefit of $356) | $ | — | $ | — | ||||
| State (Net of a net operating loss benefit of $82) | 13 | — | ||||||
| Foreign | 4 | — | ||||||
17 | — | |||||||
| Deferred: | ||||||||
| Federal | — | — | ||||||
| State | — | — | ||||||
| $ | — | $ | — | |||||
| $ | 17 | $ | — | |||||
| Twelve Months Ended December 31, | ||||||||
201 7 | 201 6 | |||||||
| Statutory federal income tax benefit | 34.0 | % | (34.0 | )% | ||||
| State income taxes, net of federal income tax benefit | 13.6 | 8.7 | ||||||
| Foreign income taxes, net of federal income tax benefit | 6.4 | (1.3 | ) | |||||
| Engineering credits | 3.4 | (5.2 | ) | |||||
| Tax effect of change in federal tax rate (from 34% to 21%) | 649.5 | |||||||
| Valuation allowance | (712.0 | ) | 26.2 | |||||
| Other | 7.8 | 5.6 | ||||||
| Effective federal income tax rate | 2.7 | % | 0.0 | % | ||||
| December 31 , 201 7 | December 31, 201 6 | |||||||
| Deferred tax assets: | ||||||||
| Net operating loss carry forwards | $ | 8,002 | $ | 12,295 | ||||
| Engineering credit carry forwards | 1,919 | 1,830 | ||||||
| Inventory reserves | 646 | 1,015 | ||||||
| Capital loss and other credit carry forwards | 0 | 21 | ||||||
| Allowance for bad debts and returns | 17 | 45 | ||||||
| Capitalized inventory costs, stock compensation and other accruals | 500 | 596 | ||||||
| Total gross deferred tax assets | 11,084 | 15,802 | ||||||
| Less valuation allowance on deferred tax assets | (11,084 | ) | (15,765 | ) | ||||
| Net deferred tax assets | 0 | 37 | ||||||
| Deferred tax liabilities: | ||||||||
| Depreciation and other | — | (37 | ) | |||||
| Total deferred tax liabilities | — | (37 | ) | |||||
| Net deferred taxes | $ | — | $ | — | ||||
| December 31 , 201 7 | December 31, 201 6 | |||||||
| Beginning Balance | $ | 29 | $ | 27 | ||||
| Increases related to tax positions taken in current year | — | — | ||||||
| Increases related to tax positions taken in prior year | — | 2 | ||||||
| Decreases due to lapse of statute of limitations | — | — | ||||||
| Related interest and penalties, net of federal tax benefit | — | — | ||||||
| Balance at December 31 | $ | 29 | $ | 29 | ||||