Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 225,853	$ 502,677
Receivable from collaboration partner	391,558	184,737
Deferred income tax assets		21,987
Prepaid expenses and other current assets	15,877	12,264
Restricted cash	930	203
Total current assets	634,218	721,868
Property and equipment, net	58,142	41,161
Intangible assets	644,299	101,000
Deferred income tax assets, non-current	57,011	15,176
Restricted cash, net of current	12,206	11,562
Goodwill	18,643	10,000
Other non-current assets	7,072	10,852
Total assets	1,431,591	911,619
Current liabilities:
Accounts payable, accrued expenses and other current liabilities	186,203	106,128
Contingent consideration	4,900	10,000
Deferred revenue		2,822
Current portion of build-to-suit lease obligation		698
Current portion of Convertible Notes, net of unamortized discount of $— and $1 at December 31, 2015 and 2014, respectively		4
Total current liabilities	266,103	119,652
Convertible Notes, net of unamortized discount of $— and $36,598 at December 31, 2015 and 2014, respectively		222,140
Contingent consideration	262,368	96,000
Build-to-suit lease obligation, excluding current portion	17,406	18,711
Other non-current liabilities	13,035	5,817
Total liabilities	$ 558,912	$ 462,320
Commitments and contingencies (Note 15)
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 shares authorized; 163,905,342 and 156,234,454 shares issued and outstanding at December 31, 2015 and 2014, respectively	$ 1,639	$ 1,562
Additional paid-in capital	684,841	505,446
Retained earnings (accumulated deficit)	186,199	(57,709)
Total stockholders’ equity	872,679	449,299
Total liabilities and stockholders’ equity	1,431,591	$ 911,619
Revolving Credit Facility [Member]
Current liabilities:
Borrowings under Credit Facility	$ 75,000