v3.21.2

Convertible notes (Schedule of Convertible Notes) (Details) |  |  |  | 12 Months Ended |
--- | --- | --- | --- | --- | ---
Apr. 30, 2020 USD ($) shares | Apr. 25, 2019 shares | Apr. 18, 2018 USD ($) $ / shares | Dec. 31, 2020 USD ($) $ / shares | Jan. 31, 2020
Short-term Debt [Line Items] |  |  |  |  |
Interest rate |  |  | 2.50% |  | 8.00%
Proceeds from Notes Payable |  |  | $ 5,779,602,000 |  |
Debt Instrument, Term |  |  | 5 years |  |
Debt Instrument, Convertible, Conversion Price | $ / shares |  |  | $ 1.50 |  |
Debt Instrument, Convertible, Number of Equity Instruments |  |  | 3,853,068 |  |
2018 Notes |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |
Debt Instrument, Convertible, Conversion Price | $ / shares |  |  |  | $ 1.38 |
Debt Instrument Dividend Liability |  |  |  | $ 500,000 |
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt |  |  |  | $ 5,300,000 |
Debt Instrument Issue Date price | $ / shares |  |  |  | $ 1.07 |
Century Skyway Limited |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |
Number of shares to sell | shares |  | 5,100 |  |  |
Century Skyway Limited | 2019 Notes |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |
Principal amount | $ 160,000 |  |  |  |
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt | 3,600,000 |  |  |  |
Principal amount to be surrendered in the disposal | $ 3,760,000 |  |  |  |
Number of shares to sell | shares | 5,100 |  |  |  |

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