Share-Based Compensation - Additional Information (Details)	1 Months Ended	3 Months Ended		9 Months Ended
	Jul. 31, 2021 USD ($) business	Sep. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2020 USD ($)	Dec. 31, 2020 shares	Aug. 03, 2018 shares	Dec. 03, 2010 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding to purchase shares of common stock (in shares) | shares		22,916,073		22,916,073		25,087,416
Warrants outstanding (in shares) | shares		1,100,000		1,100,000		900,000
Share-based payments expense		$ 15,200,000	$ 3,300,000	$ 19,200,000	$ 8,800,000
Unrecognized compensation expense related to non-vested share options		$ 19,100,000		$ 19,100,000
Weighted average period for recognition related to non-vested stock options (in years)				1 year 7 months 6 days
Total intrinsic value of shares exercised				$ 5,588,929	59,965
Total fair value of vested shares				$ 5,400,000	8,800,000
Weighted average exercise price of warrants (in dollars per share) | $ / shares		$ 4.00		$ 4.00
Weighted average remaining life of warrants (in years)				10 months 24 days
Grant date fair value	$ 12,400,000
2010 Stock Incentive Plan ("the Plan")
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance (in shares) | shares							56,800,000	31,500,000
Number of options available for issuance (in shares) | shares		16,300,000		16,300,000
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding to purchase shares of common stock (in shares) | shares		22,900,000		22,900,000
Cash received from options exercised				$ 8,400,000	$ 0
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees and directors granted | business	7
Unrecognized compensation cost related to unvested restricted shares		$ 0		$ 0