Table:
|  | As of | As of |
| --- | --- | --- |
|  | December 31, 2019 | December 31, 2018 |
| Deferred tax assets: |  |  |
| Reserves and accruals | $62 | $45 |
| Research and development credits and other credits | 1,730 | 1,635 |
| Net operating loss carry forward | 27,907 | 25,733 |
| Stock based compensation | 8,402 | 8,857 |
| Other | 11 | 26 |
| Total deferred tax assets | 38,112 | 36,296 |
| Valuation allowance | (38,112) | (36,296) |
| Deferred tax assets after valuation allowance | — | — |
| Total deferred tax liability | — | — |
| Net deferred tax assets (liabilities) | $— | $— |
Paragraphs:
In 2019 and 2018, we had pre-tax losses of $19,573 and $25,403 respectively, which are available for carry forward to offset future taxable income. We made determinations to provide full valuation allowances for our net deferred tax assets at the end of 2019 and 2018, including NOL carryforwards generated during the years, based on our evaluation of positive and negative evidence, including our history of operating losses and the uncertainty of generating future taxable income that would enable us to realize our deferred tax assets.
Deferred tax assets (liabilities) consist of the following:
In assessing the realization of deferred tax assets, management considers whether it is more likely than not that a portion of the net deferred assets will not be realized. The ultimate realization of the net deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Based on the available objective evidence, management believes it is more likely than not that the net deferred tax assets at December 31, 2019 will not be realizable. Accordingly, management has maintained a full valuation allowance against its net deferred tax assets at December 31, 2019. The net change in the total valuation allowance for the 12 months ended December 31, 2019 was an increase of $1,816.
Question:
What is the realization of the net deferred tax assets ultimately dependent upon?