Fair Value Measurements - Based Upon Sensitivity and Nature of Inputs (Details) - Derivative Warrant Liabilities [Member] |
6 Months Ended | 12 Months Ended |
---|---|---|
Jun. 30, 2019 |
Dec. 31, 2018 |
|
Measurement Input, Price Volatility [Member] | ||
Fair Value Assumptions Rate | 66.70% | 70.61% |
Measurement Input, Risk Free Interest Rate [Member] | ||
Fair Value Assumptions Rate | 1.77% | 2.53% |
Measurement Input, Expected Term [Member] | ||
Fair Value Assumptions Expected Terms | 3 years 10 months 17 days | 4 years 4 months 17 days |
Measurement Input, Expected Dividend Rate [Member] | ||
Fair Value Assumptions Rate | 0.00% | 0.00% |