Condensed Consolidated Balance Sheets - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 424,806,000	$ 358,319,000
Short-term investments	2,028,643,000	2,491,805,000
Prepaid expenses and other current assets	299,605,000	397,239,000
Total current assets	2,753,054,000	3,247,363,000
Restricted cash and cash equivalents	115,229,000	204,976,000
Restricted investments	1,199,833,000	1,361,045,000
Other investments	10,000,000	0
Property and equipment, net	335,738,000	188,603,000
Operating lease right-of-use assets	283,990,000	441,258,000
Intangible assets, net	71,792,000	82,919,000
Goodwill	182,725,000	158,725,000
Other assets	15,970,000	6,494,000
Total assets	4,968,331,000	5,691,383,000
Current liabilities
Accounts payable	26,020,000	38,839,000
Insurance reserves	922,628,000	1,378,462,000
Accrued and other current liabilities	1,047,548,000	939,865,000
Operating lease liabilities — current	48,979,000	94,199,000
Total current liabilities	2,045,175,000	2,451,365,000
Operating lease liabilities	278,773,000	382,077,000
Long-term debt, net of current portion	622,684,000	0
Other liabilities	18,606,000	3,857,000
Total liabilities	2,965,238,000	2,837,299,000
Commitments and contingencies (Note 7)
Stockholders’ equity
Preferred stock, $0.00001 par value; 1,000,000,000 shares authorized as of September 30, 2020 and December 31, 2019; no shares issued and outstanding as of September 30, 2020 and December 31, 2019	0	0
Common stock, $0.00001 par value; 18,000,000,000 Class A shares authorized as of September 30, 2020 and December 31, 2019; 308,687,414 and 293,793,151 Class A shares issued and outstanding, as of September 30, 2020 and December 31, 2019, respectively; 100,000,000 Class B shares authorized, 8,802,629 Class B shares issued and outstanding, as of September 30, 2020 and December 31, 2019	3,000	3,000
Additional paid-in capital	8,838,023,000	8,398,927,000
Accumulated other comprehensive income	7,340,000	2,725,000
Accumulated deficit	(6,842,273,000)	(5,547,571,000)
Total stockholders’ equity	2,003,093,000	2,854,084,000
Total liabilities and stockholders’ equity	$ 4,968,331,000	$ 5,691,383,000
Preferred stock shares authorized (in shares)	1,000,000,000	1,000,000,000