| 8. | INCOME TAXES |
| Year Ended | ||||||||
| December 31, 2017 | December 30, 2016 | |||||||
| Current tax expense | $ | 25 | $ | — | ||||
| Deferred tax benefit | (2,743 | ) | (13,997 | ) | ||||
| Change in valuation allowance | 2,743 | | 13,997 | |||||
| Total provision for income taxes | $ | 25 | $ | — | ||||
| At | ||||||||
| December 31, 2017 | December 30, 2016 | |||||||
| Tax benefit at U.S. statutory rate | $ | (15,155 | ) | $ | (13,117 | ) | ||
| State taxes, net of federal benefit | (822 | ) | (1,146 | ) | ||||
| Impact of tax reform rate change | 11,696 | — | ||||||
| Other | 1,562 | 266 | ||||||
| Valuation allowance – tax reform rate change | (11,696 | ) | — | |||||
| Valuation allowance – other changes | 14,440 | 13,997 | ||||||
| Total provision for income taxes | $ | 25 | $ | — | ||||
| Year Ended | ||||||||
| December 31, 2017 | December 30, 2016 | |||||||
| Net operating loss carryforwards | $ | 16,834 | $ | 10,998 | ||||
| Research and development tax credits | 420 | — | ||||||
| Property, plant and equipment | 127 | 637 | ||||||
| Intangible assets | 3,281 | 5,603 | ||||||
| Accruals | 503 | 415 | ||||||
| Other | 861 | 1,629 | ||||||
| Gross deferred tax assets | 22,026 | 19,282 | ||||||
| Less valuation allowance | (22,026 | ) | (19,282 | ) | ||||
| Net deferred tax assets | — | — | ||||||
| Net deferred tax asset (liability) | $ | — | $ | — | ||||
| December 31, 2017 | ||||
| Balance at beginning of fiscal year | $ | — | ||
| Gross amount of increases for current year tax positions | 140 | |||
| Balance at ending of fiscal year | $ | 140 | ||