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Stock Options - Schedule of Stock Options Valuation Assumptions Using a Black-Scholes Option Pricing Model (Details) - $ / shares
3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]    
Estimated dividend yield 0.00% 0.00%
Weighted-average expected stock price volatility 68.46% 68.19%
Weighted-average risk-free interest rate 2.42% 2.45%
Expected life of options (in years) 6 years 9 months 25 days 6 years 4 months 9 days
Weighted-average fair value per option $ 9.31 $ 8.90