v3.20.2

Income taxes: (Details) - Provision for Income Taxes - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Provision for Income Taxes [Abstract] |  |  |
Computed expected benefit of income taxes | $ (1,891,163) | $ (865,648) | $ (966,289)
Stock-based compensation | 1,286,201 | 332,082 | 68,037
Non-deductible interest expense | 25,722 | 25,658 | 52,648
Impact of change in tax rate |  | 5,163,267 | 0
Expiry of tax credits | 18,486 |  |
True up of prior year balances | 37,917 |  |
Increase (decrease) in valuation allowance | 522,837 | (4,655,359) | 845,604
Income tax provision |  |  | $ 0

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