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Stock-Based Compensation - Valuing Stock Options (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	71.10%
Risk-free interest rate	0.30%
Expected life (in years)	3 years 6 months
Expected dividend yield	0.00%
Weighted average grant date fair value (in dollars per share)	$ 5.67
Consideration transferred	$ 7.1
Options \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		1 month 6 days
Options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years 8 months 12 days