Share-Based Compensation - Option Valuation (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Assumptions to determine fair value of options granted on weighted average basis:
Risk-free interest rate	0.39%	2.16%	0.71%	2.48%
Expected term (in years)	5 years 11 months 26 days	5 years 11 months 19 days	6 years 2 months 4 days	6 years 2 months 4 days
Expected volatility	79.38%	78.88%	79.71%	78.35%