Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 358,319	$ 517,690
Short-term investments	2,491,805	1,520,180
Prepaid expenses and other current assets	397,239	282,572
Total current assets	3,247,363	2,320,442
Restricted cash and cash equivalents	204,976	187,374
Restricted investments	1,361,045	863,713
Property and equipment, net	188,603	109,257
Operating lease right of use assets	441,258
Intangible assets, net	82,919	117,733
Goodwill	158,725	152,085
Other assets	6,494	9,439
Total assets	5,691,383	3,760,043
Current liabilities
Accounts payable	38,839	32,343
Insurance reserves	1,378,462	810,273
Accrued and other current liabilities	939,865	606,203
Operating lease liabilities — current	94,199
Total current liabilities	2,451,365	1,448,819
Operating lease liabilities	382,077
Other liabilities	3,857	30,458
Total liabilities	2,837,299	1,479,277
Commitments and contingencies (Note 8)
Redeemable convertible preferred stock, $0.00001 par value; no and 227,328,900 shares authorized as of December 31, 2019 and December 31, 2018, respectively; no and 219,175,709 shares issued and outstanding as of December 31, 2019 and December 31, 2018, respectively	0	5,152,047
Stockholders’ equity (deficit)
Preferred stock, $0.00001 par value; 1,000,000,000 and no shares authorized as of December 31, 2019 and December 31, 2018, respectively; no shares issued and outstanding as of December 31, 2019 and December 31, 2018	0	0
Common stock, $0.00001 par value; 18,000,000,000 Class A shares and 340,000,000 shares authorized, 293,793,151 Class A shares and 22,438,472 shares issued and outstanding, as of December 31, 2019 and December 31, 2018, respectively; 100,000,000 and no Class B shares authorized, 8,802,629 and no Class B shares issued and outstanding, as of December 31, 2019 and December 31, 2018, respectively	3	0
Additional paid-in capital	8,398,927	73,916
Accumulated other comprehensive income	2,725	133
Accumulated deficit	(5,547,571)	(2,945,330)
Total stockholders’ equity (deficit)	2,854,084	(2,871,281)
Total liabilities, redeemable convertible preferred stock and stockholders’ equity (deficit)	$ 5,691,383	$ 3,760,043