Stockholders' Equity (Weighted Average Assumptions of Fair Value Options Using Black-Scholes Option-Pricing Model) (Details)	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Option-Pricing Model Weighted Average Assumptions
Dividend yield (percent)	0.00%	0.00%		0.00%	0.00%
Risk-free interest rate, minimum (percent)	0.31%		1.88%	0.31%	1.88%
Risk-free interest rate, maximum (percent)	0.32%		2.36%	0.66%	2.57%
Expected life (in years)	5 years	5 years		5 years	5 years
Historical volatility, minimum (percent)	51.91%		43.42%	46.50%	43.42%
Historical volatility, maximum (percent)	51.94%		43.69%	51.94%	43.85%