CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 652,723	$ 649,666
Marketable securities	996,392	1,063,679
Accounts receivable, net of allowances of $5,670 and $2,851 as of September 30, 2020 and December 31, 2019, respectively	339,274	316,367
Prepaid expenses and other current assets	44,537	37,522
Total current assets	2,032,926	2,067,234
Property and equipment, net	76,294	91,992
Operating lease right-of-use assets	164,803	188,251
Goodwill and intangible assets, net	13,814	14,576
Restricted cash	9,221	25,339
Other assets	3,980	5,925
Total assets	2,301,038	2,393,317
Current liabilities:
Accounts payable	41,703	34,334
Accrued expenses and other current liabilities	147,946	141,823
Total current liabilities	189,649	176,157
Operating lease liabilities	150,162	173,392
Other liabilities	26,623	20,063
Total liabilities	366,434	369,612
Commitments and contingencies
Stockholders’ equity:
Common stock	6	6
Additional paid-in capital	4,475,425	4,229,778
Accumulated other comprehensive income	2,063	647
Accumulated deficit	(2,542,890)	(2,206,726)
Total stockholders’ equity	1,934,604	2,023,705
Total liabilities and stockholders’ equity	$ 2,301,038	$ 2,393,317