| 17. | Expenses by nature |
Expenses incurred for the years ended December 31, 2017, 2016 and 2015 are as follows:
| Year ended December 31 | 2017 | 2016 | 2015 | |||||||||
| Personnel expenses | ||||||||||||
| Salaries, fees and short-term benefits | $ | 5,903,669 | $ | 5,804,883 | $ | 3,908,579 | ||||||
| Share-based payments | 490,769 | 1,340,001 | 1,460,316 | |||||||||
| 6,394,438 | 7,144,884 | 5,368,895 | ||||||||||
| Amortization and derecognition | 97,794 | 1,433,573 | 690,934 | |||||||||
| Research and development | 3,538,547 | 2,270,964 | 3,723,317 | |||||||||
| Manufacturing | 955,160 | 1,062,684 | 916,939 | |||||||||
| Inventory material costs | 3,079,397 | 2,482,986 | 1,563,344 | |||||||||
| Write-down (write-up) of inventory | 385,289 | (108,817 | ) | 40,920 | ||||||||
| Medical affairs | 1,108,090 | 1,040,755 | 865,368 | |||||||||
| Administration | 1,724,584 | 1,526,682 | 948,226 | |||||||||
| Selling and logistics | 5,395,373 | 5,355,876 | 3,103,722 | |||||||||
| Professional fees | 801,882 | 559,287 | 140,573 | |||||||||
| $ | 23,480,554 | $ | 22,768,874 | $ | 17,362,238 | |||||||