CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 1,416,224	$ 1,163,980
Marketable securities-available-for-sale	279,631	274,343
Accounts receivable	302,680	307,598
Inventory	6,527	6,967
Prepaid expenses and other current assets	53,563	79,366
Total current assets	2,058,625	1,832,254
Restricted cash and investments	1,014	1,006
Long term investments	115,563	99,199
Inventory	6,166	3,438
Property and equipment, net	339,122	319,751
Finance lease right-of use assets, net	30,348
Other intangible assets, net	204,596	215,364
Goodwill	155,593	155,593
Other assets, net	36,606	19,157
Total assets	2,947,633	2,645,762
Current liabilities:
Accounts payable	66,184	103,827
Accrued compensation	53,697	60,176
Interest payable	30	29
Accrued and other current liabilities	210,474	229,401
Finance lease liabilities	791
Acquisition-related contingent consideration	35,929	31,844
Total current liabilities	367,105	425,277
Convertible senior notes	17,862	17,434
Acquisition-related contingent consideration	250,071	255,157
Finance lease liabilities	31,643
Other liabilities	33,761	21,927
Total liabilities	700,442	719,795
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; none issued or outstanding as of June 30, 2019 and December 31, 2018
Common stock, $0.001 par value; 400,000,000 shares authorized; 214,865,720 and 213,274,660 shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively	215	213
Additional paid-in capital	3,925,975	3,813,678
Accumulated other comprehensive loss	(8,965)	(10,165)
Accumulated deficit	(1,670,034)	(1,877,759)
Total stockholders' equity	2,247,191	1,925,967
Total liabilities and stockholders' equity	$ 2,947,633	$ 2,645,762