Condensed Consolidated Balance Sheets (unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 874,684	$ 845,035
Marketable securities	11,958	11,952
Accounts receivable, net	76,983	64,297
Receivable from collaboration partners	24,025	26,970
Inventory	49,025	34,446
Advances to manufacturers	1,149	12,288
Prepaid expenses and other current assets	39,953	20,571
Total current assets	1,077,777	1,015,559
Property and equipment, net	32,141	32,476
Intangible assets, net	8,550	8,730
Other assets	3,429	3,342
Total assets	1,121,897	1,060,107
Current liabilities:
Accounts payable	2,889	7,315
Accrued liabilities	95,439	88,279
Payable to collaboration partner	77,460	79,799
Income tax payable	53	70
Deferred revenue - current portion	18,797	18,773
Total current liabilities	194,638	194,236
Deferred revenue - non-current portion	32,757	34,885
Other long-term liabilities	1,836	1,821
Total liabilities	229,231	230,942
Commitments and contingencies (see Notes 3 and 9)
Stockholders’ equity:
Preferred stock, $0.0001 par value; 1,000,000 shares authorized; none issued and outstanding	0	0
Common stock, $0.0001 par value; 150,000,000 shares authorized at March 31, 2015 and December 31, 2014, respectively; shares issued and outstanding 76,791,635 and 75,933,661 at March 31, 2015 and December 31, 2014, respectively	8	8
Additional paid-in capital	1,018,985	959,637
Accumulated other comprehensive loss	(2)	(8)
Accumulated deficit	(126,325)	(130,472)
Total stockholders’ equity	892,666	829,165
Total liabilities and stockholders’ equity	$ 1,121,897	$ 1,060,107