CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 501,706	$ 25,055
Marketable securities	143,399	135,602
Accounts receivable, net	32,205	25,155
Contract assets	1,470	1,552
Prepaid expenses and other current assets	16,898	9,373
Total current assets	695,678	196,737
Long-term investments	16,169	0
Property and equipment, net	92,485	73,210
Goodwill	4,083	4,083
Acquired intangible assets, net	62	156
Deferred contract acquisition costs, noncurrent	21,141	15,940
Restricted cash	6,660	6,371
Other noncurrent assets	3,569	1,883
Total assets	839,847	298,380
Current liabilities:
Accounts payable	9,517	14,285
Accrued expenses and other current liabilities	23,121	15,699
Note payable, current portion	37	255
Liability for early exercise of unvested stock options	14,629	14,323
Deferred revenue	29,835	16,817
Total current liabilities	77,139	61,379
Build-to-suit lease financing obligation	10,501	10,443
Deferred revenue, noncurrent	816	220
Redeemable convertible preferred stock warrant liability	0	1,618
Other noncurrent liabilities	10,993	6,704
Total liabilities	99,449	80,364
Commitments and contingencies (Note 7)
Redeemable Convertible Preferred Stock
Redeemable convertible preferred stock; $0.001 par value; 168,108 and 168,108 shares authorized as of September 30, 2019 and December 31, 2018, respectively; zero and 165,658 shares issued and outstanding with aggregate liquidation preference of zero and $332,041 as of September 30, 2019 and December 31, 2018, respectively	0	331,521
Stockholders’ Equity (Deficit)
Additional paid-in capital	1,013,582	82,345
Accumulated deficit	(273,551)	(195,878)
Accumulated other comprehensive income (loss)	73	(57)
Total stockholders’ equity (deficit)	740,398	(113,505)
Total liabilities, redeemable convertible preferred stock and stockholders’ equity (deficit)	839,847	298,380
Class A common stock
Stockholders’ Equity (Deficit)
Common stock	87	0
Class B common stock
Stockholders’ Equity (Deficit)
Common stock	$ 207	$ 85