CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 521,439	$ 452,297
Marketable securities-available-for-sale	186,344	147,966
Restricted cash and investments	516	500
Accounts receivable	114,450	57,933
Inventory	1,783	358
Prepaid expenses and other current assets	17,843	20,519
Total current assets	842,375	679,573
Restricted cash and investments	13,977	14,000
Long term investment	35,248
Inventory	17,555	19,078
Property and equipment, net	86,006	81,790
Other assets, net	12,279	2,036
Total assets	1,007,440	796,477
Current liabilities:
Accounts payable	30,085	24,462
Accrued compensation	38,117	34,422
Interest payable	762	1,841
Accrued and other current liabilities	86,531	62,270
Deferred revenue-collaborative agreements	12,512	12,880
Convertible senior notes		85,186
Total current liabilities	168,007	221,061
Convertible senior notes	619,893	589,981
Other liabilities	48,385	54,552
Deferred revenue-collaborative agreements		12,511
Total liabilities	$ 836,285	$ 878,105
Stockholders' equity (deficit):
Preferred stock, $0.001 par value; 5,000,000 shares authorized; none issued or outstanding as of September 30, 2015 and December 31, 2014
Common stock, $0.001 par value; 400,000,000 shares authorized; 186,650,249 and 170,876,619 shares issued and outstanding as of September 30, 2015 and December 31, 2014, respectively	$ 187	$ 171
Additional paid-in capital	1,950,764	1,701,904
Accumulated other comprehensive (loss) income	(809)	1,815
Accumulated deficit	(1,778,987)	(1,785,518)
Total stockholders' equity (deficit)	171,155	(81,628)
Total liabilities and stockholders' equity (deficit)	$ 1,007,440	$ 796,477