Summary of Significant Accounting Policies - Company's Condensed Consolidated Balance Sheet (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2022	Dec. 31, 2020
Accounting Policies [Line Items]
Premium deficiency reserve		$ 0	$ 7,239	$ 109,905
Total current liabilities		261,115	431,507	371,901
Total liabilities		284,277	451,733	410,764
Accumulated deficit		(2,159,794)	(1,946,433)	(1,616,015)	$ 1,616,000
Total stockholders' equity		286,394	356,887	540,040		$ (613,193)
Total liabilities and stockholders' equity		570,671	808,620	950,804
Premium deficiency reserve expense (benefit)		(7,239)	(93,517)	110,628
Operating Expenses		2,242,262	3,848,334	2,108,988
Operating Income (Loss)		(208,542)	(371,647)	(636,992)
Net Income (Loss)		$ (213,361)	$ (339,567)	$ (587,756)
Net loss per share attributable to Class A and Class B common stockholders - basic (in dollars per share)	[1]	$ (0.44)	$ (0.71)	$ (1.42)
Net loss per share attributable to Class A and Class B common stockholders - diluted (in dollars per share)	[1]	$ (0.44)	$ (0.71)	$ (1.42)
Previously reported
Accounting Policies [Line Items]
Premium deficiency reserve			$ 16,388	$ 110,628
Total current liabilities			440,656	372,624
Total liabilities			460,882	411,487
Accumulated deficit			(1,955,582)	(1,616,738)
Total stockholders' equity			347,738	539,317
Total liabilities and stockholders' equity			808,620	950,804
Premium deficiency reserve expense (benefit)		$ (16,388)	(94,240)
Operating Expenses		2,233,113	3,847,611
Operating Income (Loss)		(199,393)	(370,924)
Net Income (Loss)		$ (204,212)	$ (338,844)
Net loss per share attributable to Class A and Class B common stockholders - basic (in dollars per share)		$ (0.42)	$ (0.71)
Net loss per share attributable to Class A and Class B common stockholders - diluted (in dollars per share)		$ (0.42)	$ (0.71)
Effect of Change
Accounting Policies [Line Items]
Premium deficiency reserve			$ (9,149)	(723)
Total current liabilities			(9,149)	(723)
Total liabilities			(9,149)	(723)
Accumulated deficit			9,149	723
Total stockholders' equity			9,149	723
Total liabilities and stockholders' equity			0	$ 0
Premium deficiency reserve expense (benefit)		$ 9,149	723
Operating Expenses		9,149	723
Operating Income (Loss)		(9,149)	(723)
Net Income (Loss)		$ (9,149)	$ (723)
Net loss per share attributable to Class A and Class B common stockholders - basic (in dollars per share)		$ (0.02)	$ 0
Net loss per share attributable to Class A and Class B common stockholders - diluted (in dollars per share)		$ (0.02)	$ 0

[1] (1) Because the Company had a Net loss during the years ended December 31, 2023, 2022, and 2021, the Company's potentially dilutive securities, which include stock options, restricted stock units, preferred stock, and warrants to purchase shares of common stock and preferred stock, have been excluded from the computation of diluted net loss per share, as the effect would be anti-dilutive.