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Summary of Significant Accounting Policies - Schedule of fair value valuation (Details)
Dec. 31, 2018
$ / shares
Dec. 31, 2017
$ / shares
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Expected term (in years) 2 years 3 years
Fair value of underlying shares    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 19.02 3.00
Volatility    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.550 0.550
Risk-free interest rate    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.0248 0.0198
Dividend yield    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0 0