CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	[1]
Current assets:
Cash and cash equivalents	$ 1,112,179	$ 899,509
Marketable securities—available-for-sale	263,134	270,136
Accounts receivable	247,736	266,299
Inventory	5,993	6,482
Prepaid expenses and other current assets	71,317	62,428
Total current assets	1,700,359	1,504,854
Restricted cash and investments	1,009	925
Long term investments	121,381	134,356
Inventory	5,425	7,966
Property and equipment, net	300,767	259,763
Other intangible assets, net	220,748	236,901
Goodwill	155,593	155,593
Other assets, net	14,665	2,224
Total assets	2,519,947	2,302,582
Current liabilities:
Accounts payable	95,478	67,671
Accrued compensation	58,027	74,550
Interest payable	100	33
Accrued and other current liabilities	231,571	198,901
Convertible senior notes	7,648	7,393
Acquisition-related contingent consideration	29,665	26,848
Total current liabilities	422,489	375,396
Convertible senior notes	17,224	16,608
Acquisition-related contingent consideration	256,335	260,152
Other liabilities	21,000	19,797
Total liabilities	717,048	671,953
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; none issued or outstanding as of September 30, 2018 and December 31, 2017
Common stock, $0.001 par value; 400,000,000 shares authorized; 212,754,024 and 211,262,906 shares issued and outstanding as of September 30, 2018 and December 31, 2017, respectively	213	211
Additional paid-in capital	3,759,030	3,627,433
Accumulated other comprehensive loss	(9,522)	(7,010)
Accumulated deficit	(1,946,822)	(1,990,005)
Total stockholders' equity	1,802,899	1,630,629
Total liabilities and stockholders' equity	$ 2,519,947	$ 2,302,582

[1] The condensed consolidated balance sheet at December 31, 2017 has been derived from the audited financial statements at that date.