Stockholders' Equity - Weighted Average Assumptions of Fair Value Options Using Black-Scholes Option-Pricing Model (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Option-Pricing Model Weighted Average Assumptions
Dividend yield (percent)	0.00%	0.00%	0.00%	0.00%
Risk-free interest rate, minimum (percent)	0.77%	0.31%	0.46%	0.31%
Risk-free interest rate, maximum (percent)	0.84%	0.32%	0.84%	0.66%
Expected life (in years)	5 years	5 years	5 years	5 years
Historical volatility, minimum (percent)	54.31%	51.91%	53.94%	46.50%
Historical volatility, maximum (percent)	54.55%	51.94%	54.55%	51.94%