Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 952,137	$ 758,505
Marketable securities	723,141	531,604
Other investment and investment receivable	20,017
Tenant improvement receivable	19	3,112
Prepaid expenses	24,133	21,171
Receivables and other current assets	5,901	8,377
Total current assets	1,725,348	1,322,769
Marketable securities	323,772	324,193
Property, plant and equipment, net	232,863	199,606
Intangible assets, net	14,109	16,931
Goodwill	13,128	13,128
Restricted cash and other non-current assets	42,569	23,940
Total assets	2,351,789	1,900,567
Current Liabilities:
Accounts payable	12,891	12,873
Accrued expenses and other current liabilities	88,335	57,065
Deferred revenue, current portion	22,575	25,674
Collaboration research advancement, current portion	7,842
Total current liabilities	131,643	95,612
Deferred revenue, net of current portion	22,256	21,763
Collaboration research advancement, net of current portion	37,676
Contingent consideration	3,074	2,231
Financing lease obligation, net of current portion	153,716	154,749
Other non-current liabilities	2,634	2,780
Total liabilities	350,999	277,135
Commitments and contingencies (Note 8)
Stockholders’ Equity:
Preferred stock, $0.01 par value, 5,000 shares authorized; 0 shares issued and outstanding at September 30, 2018 and December 31, 2017
Common stock, $0.01 par value, 125,000 shares authorized; 54,678 and 49,406 shares issued and outstanding at September 30, 2018 and December 31, 2017, respectively	547	494
Additional paid-in capital	3,355,491	2,540,951
Accumulated other comprehensive loss	(5,463)	(4,205)
Accumulated deficit	(1,349,785)	(913,808)
Total stockholders’ equity	2,000,790	1,623,432
Total liabilities and stockholders’ equity	$ 2,351,789	$ 1,900,567