Financial Risk Management and Financial Instruments - Summary of Assumption Used to Estimate Fair Value of Warrants (Details) - Warrants |
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2018
USD ($)
yr
|
Dec. 31, 2017
USD ($)
yr
|
Dec. 31, 2016
USD ($)
yr
|
|
| Bottom Of Range [Member] | |||
| Disclosure Of Significant Unobservable Inputs Used In Fair Value Measurement Of Liabilities [Line Items] | |||
| Expected term (years) | yr | 0.6 | 0.9 | 1.85 |
| Risk free rate (%) | 1.98% | 1.17% | 0.77% |
| Volatility (%) | 32.50% | 30.00% | 35.00% |
| Share price (US$) | $ | $ 113.50 | $ 50.70 | $ 42.18 |
| Top of range | |||
| Disclosure Of Significant Unobservable Inputs Used In Fair Value Measurement Of Liabilities [Line Items] | |||
| Expected term (years) | yr | 1.71 | 1.6 | 2.09 |
| Risk free rate (%) | 2.73% | 1.76% | 1.14% |
| Volatility (%) | 40.00% | 37.50% | 37.50% |
| Share price (US$) | $ | $ 180.83 | $ 120.50 | $ 44.40 |