Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 421,150	$ 502,677
Short-term investments	76,357
Receivable from collaboration partner	197,157	184,737
Deferred income tax assets	9,533	21,987
Prepaid expenses and other current assets	18,640	12,264
Restricted cash	616	203
Total current assets	723,453	721,868
Property and equipment, net	44,291	41,161
Intangible assets	101,000	101,000
Deferred income tax assets, non-current	32,868	15,176
Restricted cash, net of current	12,723	11,562
Goodwill	10,000	10,000
Other non-current assets	6,355	10,852
Total assets	930,690	911,619
Current liabilities:
Accounts payable, accrued expenses and other current liabilities	118,850	106,128
Contingent consideration	10,000	10,000
Deferred revenue	565	2,822
Current portion of build-to-suit lease obligation	196	698
Current portion of Convertible Notes, net of unamortized discount of $18,650 and $1 at June 30, 2015 and December 31, 2014, respectively	149,098	4
Total current liabilities	278,709	119,652
Convertible Notes, net of unamortized discount of $- and $36,598 at June 30, 2015 and December 31, 2014, respectively		222,140
Contingent consideration	101,013	96,000
Build-to-suit lease obligation, excluding current portion	16,920	18,711
Other non-current liabilities	6,525	5,817
Total liabilities	$ 403,167	$ 462,320
Commitments and contingencies (Note 14)
Stockholders' equity:
Preferred stock, $0.01 par value per share; 1,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.01 par value per share; 340,000,000 and 170,000,000 shares authorized at June 30, 2015 and December 31, 2014, respectively; 79,860,733 and 78,117,227 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively	$ 799	$ 781
Additional paid-in capital	561,759	506,227
Accumulated other comprehensive loss	(34)
Accumulated deficit	(35,001)	(57,709)
Total stockholders' equity	527,523	449,299
Total liabilities and stockholders' equity	$ 930,690	$ 911,619