CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 740,833	$ 649,666
Marketable securities	995,875	1,063,679
Accounts receivable, net of allowances of $5,889 and $2,851 as of March 31, 2020 and December 31, 2019, respectively	212,215	316,367
Prepaid expenses and other current assets	32,565	37,522
Total current assets	1,981,488	2,067,234
Property and equipment, net	90,357	91,992
Operating lease right-of-use assets	172,927	188,251
Goodwill and intangible assets, net	14,319	14,576
Restricted cash	23,791	25,339
Other assets	5,730	5,925
Total assets	2,288,612	2,393,317
Current liabilities:
Accounts payable	37,749	34,334
Accrued expenses and other current liabilities	133,050	141,823
Total current liabilities	170,799	176,157
Operating lease liabilities	158,298	173,392
Other liabilities	21,035	20,063
Total liabilities	350,132	369,612
Commitments and contingencies
Stockholders’ equity:
Common stock	6	6
Additional paid-in capital	4,288,603	4,229,778
Accumulated other comprehensive income (loss)	(2,207)	647
Accumulated deficit	(2,347,922)	(2,206,726)
Total stockholders’ equity	1,938,480	2,023,705
Total liabilities and stockholders’ equity	$ 2,288,612	$ 2,393,317