CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 134,648	$ 122,509
Marketable securities	507,568	505,304
Accounts receivable net of allowances of $2,600 and $3,097 as of March 31, 2019 and December 31, 2018, respectively	161,108	221,932
Prepaid expenses and other current assets	43,623	39,607
Total current assets	846,947	889,352
Property and equipment, net	83,031	81,512
Operating lease right-of-use assets	160,802	145,203
Goodwill and intangible assets, net	13,728	14,071
Restricted cash	25,724	11,724
Other assets	11,008	10,869
Total assets	1,141,240	1,152,731
Current liabilities:
Accounts payable	30,320	22,169
Accrued expenses and other current liabilities	93,206	86,258
Operating lease liabilities	123,526	108,427
Operating lease liabilities	162,359	151,395
Other liabilities	23,945	22,073
Total liabilities	309,830	281,895
Commitments and contingencies
Redeemable convertible preferred stock, $0.00001 par value, 928,676 shares authorized; 308,373 shares issued and outstanding as of March 31, 2019 and December 31, 2018, respectively	1,465,399	1,465,399
Stockholders’ equity (deficit):
Common stock, $0.00001 par value, 1,932,500 shares authorized; 127,371 and 127,298 shares issued and outstanding as of March 31, 2019 and December 31, 2018, respectively	1	1
Additional paid-in capital	253,016	252,212
Accumulated other comprehensive loss	(231)	(1,421)
Accumulated deficit	(886,775)	(845,355)
Total stockholders’ equity (deficit)	(633,989)	(594,563)
Total liabilities, redeemable convertible preferred stock, and stockholders’ equity (deficit)	$ 1,141,240	$ 1,152,731