Stock-Based Compensation - Performance-based Awards (Details) - USD ($) $ in Thousands	3 Months Ended							12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs Granted (in shares)								6,204,000
Performance-based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense								$ 17,200	$ 7,300
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs Granted (in shares)								3,102
Vested (in shares)								1,100
Restricted stock units | Fair Market Value
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs Granted (in shares)	22,000	27,000	21,000	436,000		188,000
Vested (in shares)		5,000		4,000
Restricted stock units | Monte-Carlo
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs Granted (in shares)	32,000			300,000	50,000		300,000
Vested (in shares)				150,000	25,000		219,000
Employee and non-employee stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)								457,000
Stock-based compensation expense								$ 50,171	$ 28,624	$ 14,198
Employee and non-employee stock options | Black-Scholes Merton
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)		10,000		129,000
Options Vested (in shares)		10,000
Employee and non-employee stock options | Monte-Carlo
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)				150,000			200,000
Options Vested (in shares)				75,000			138,000