CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 1,936,998	$ 553,398
Marketable securities	0	157,649
Restricted cash	8,175	93,880
Accounts receivable	75,283	262,012
Unbilled receivable	34,678	0
Prepaid expenses and other current assets	119,047	181,264
Total current assets	2,174,181	1,248,203
Restricted cash	1,653	1,460
Property and equipment, net	214,751	179,954
Intangible assets, net	5,027	5,725
Goodwill	131,989	135,379
Other non-current assets	38,340	11,758
Total assets	2,565,941	1,582,479
Current liabilities:
Accounts payable	59,564	54,332
Accrued expenses	323,867	142,468
Deferred revenue	1,262,360	273,228
Current portion of finance lease liabilities	103,987	105,862
Other current liabilities	3,637	3,782
Total current liabilities	1,753,415	579,672
Convertible notes payable	323,102	322,035
Non-current finance lease liabilities	0	40,083
Other non-current liabilities	28,088	13,480
Total liabilities	2,104,605	955,270
Commitments and contingencies
Preferred stock, $0.01 par value, 2,000,000 shares authorized at September 30, 2021 and December 31, 2020; no shares issued and outstanding at September 30, 2021 and December 31, 2020	0	0
Stockholders' equity:
Common stock, $0.01 par value, 600,000,000 shares authorized at September 30, 2021 and December 31, 2020; and 75,973,523 shares issued and 75,415,774 shares outstanding at September 30, 2021 and 71,350,365 shares issued and 70,953,739 shares outstanding at December 31, 2020	760	714
Additional paid-in capital	3,310,513	2,535,476
Accumulated deficit	(2,771,666)	(1,874,199)
Treasury stock, 557,749 shares, cost basis at September 30, 2021 and 396,626 shares, cost basis at December 31, 2020	(79,132)	(41,806)
Accumulated other comprehensive income	861	7,024
Total stockholders’ equity	461,336	627,209
Total liabilities and stockholders’ equity	$ 2,565,941	$ 1,582,479