CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	[1]
Current assets:
Cash and cash equivalents	$ 1,299,704	$ 1,163,980
Marketable securities—available-for-sale	281,320	274,343
Accounts receivable	244,081	307,598
Inventory	7,129	6,967
Prepaid expenses and other current assets	72,266	79,366
Total current assets	1,904,500	1,832,254
Restricted cash and investments	995	1,006
Long term investments	120,188	99,199
Inventory	3,876	3,438
Property and equipment, net	338,331	319,751
Other intangible assets, net	209,980	215,364
Goodwill	155,593	155,593
Other assets, net	20,698	19,157
Total assets	2,754,161	2,645,762
Current liabilities:
Accounts payable	70,363	103,827
Accrued compensation	48,522	60,176
Interest payable	89	29
Accrued and other current liabilities	211,302	229,401
Acquisition-related contingent consideration	34,239	31,844
Total current liabilities	364,515	425,277
Convertible senior notes	17,647	17,434
Acquisition-related contingent consideration	252,761	255,157
Other liabilities	33,671	21,927
Total liabilities	668,594	719,795
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; none issued or outstanding as of March 31, 2019 and December 31, 2018
Common stock, $0.001 par value; 400,000,000 shares authorized; 214,320,605 and 213,274,660 shares issued and outstanding as of March 31, 2019 and December 31, 2018, respectively	214	213
Additional paid-in capital	3,869,952	3,813,678
Accumulated other comprehensive loss	(9,247)	(10,165)
Accumulated deficit	(1,775,352)	(1,877,759)
Total stockholders' equity	2,085,567	1,925,967
Total liabilities and stockholders' equity	$ 2,754,161	$ 2,645,762

[1] The condensed consolidated balance sheet at December 31, 2018 has been derived from the audited financial statements at that date.