| Years ended December 31, | ||||||||
| Current | 2017 | 2016 | ||||||
| Federal | $ | 1,738,132 | $ | 1,058,714 | ||||
| State | 117 | (3,501 | ) | |||||
| Total current provision for income taxes | 1,738,249 | 1,055,213 | ||||||
| Deferred | ||||||||
| Federal | (31,760 | ) | 59,712 | |||||
| State | --- | --- | ||||||
| Total deferred provision for income taxes | (31,760 | ) | 59,712 | |||||
| Total provision for income taxes | $ | 1,706,489 | $ | 1,114,925 | ||||
| Years ended December 31, | ||||||||||||||||
| 2017 | 2016 | |||||||||||||||
($) | Tax rate | ($) | Tax rate | |||||||||||||
| Income taxes at statutory federal income tax rate of 34% | $ | 1,887,000 | 34.0 | % | $ | 1,257,000 | 34.0 | % | ||||||||
| State income taxes, net of Federal benefit | --- | --- | (2,000 | ) | --- | |||||||||||
| Domestic Production Activities tax benefit | (160,000 | ) | (2.9 | ) | (104,000 | ) | (2.8 | ) | ||||||||
| Nondeductible expenses | 1,000 | --- | 1,000 | --- | ||||||||||||
| Research & development credits | (34,000 | ) | (0.6 | ) | (30,000 | ) | (0.8 | ) | ||||||||
| Non-taxable dividends | (5,000 | ) | (0.09 | ) | --- | --- | ||||||||||
| Deferred tax asset reduction for federal tax rate change | 21,000 | 0.4 | --- | --- | ||||||||||||
| Other, net | (4,000 | ) | (0.1 | ) | (7,000 | ) | (0.2 | ) | ||||||||
| Provision for income taxes | $ | 1,706,000 | 30.7 | % | $ | 1,115,000 | 30.2 | % | ||||||||
| Years ended December 31, | ||||||||
| 2017 | 2016 | |||||||
| Deferred tax assets | ||||||||
| Accounts receivable | $ | 4,456 | $ | 5,760 | ||||
| Inventories | 9,104 | 14,163 | ||||||
| Accrued expenses | 157,610 | 234,594 | ||||||
| Total deferred tax assets | 171,170 | 254,517 | ||||||
| Deferred tax liabilities | ||||||||
| Depreciation on property, plant and equipment | (81,145 | ) | (161,657 | ) | ||||
| Unrealized gain on marketable securities | (123,880 | ) | (90,478 | ) | ||||
| Total deferred tax liabilities | (205,025 | ) | (252,135 | ) | ||||
| Net deferred tax (liability)/asset | $ | (33,855 | ) | $ | 2,382 | |||