Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 56,350	$ 35,688
Available-for-sale securities	6,000	88,340
Restricted cash	101	101
Accounts receivable	2,051	3,313
Prepaid expenses and other current assets	6,419	4,654
Total current assets	70,921	132,096
Restricted cash	584	584
Property and equipment, net	19,964	14,502
Other assets	125	144
Intangible assets, net	1,285	1,525
In-process research and development	6,200	6,200
Goodwill	3,605	3,605
Total assets	102,684	158,656
Current liabilities:
Accounts payable, accrued expenses and other	38,702	37,236
Deferred revenues	55,072	59,275
Deferred rent	1,488	1,285
Long-term debt, current portion		13,346
Total current liabilities	95,262	111,142
Deferred revenues, net of current portion	13,963	35,682
Deferred rent, net of current portion	5,356	5,401
Deferred tax incentives, net of current portion	1,307	496
Long-term debt, net of current portion	126,261	106,806
Accrued interest	1,200	1,200
Total liabilities	243,349	260,727
Non-controlling interest	$ 481	$ 69
Stockholders' deficit:
Preferred stock, $0.01 par value: 10,000 shares authorized at September 30, 2015 and December 31, 2014; no shares issued or outstanding at September 30, 2015 or December 31, 2014
Common stock, $0.01 par value: 200,000 shares authorized at September 30, 2015 and December 31, 2014; 115,101 and 106,697 shares issued and outstanding at September 30, 2015 and December 31, 2014, respectively	$ 1,151	$ 1,067
Additional paid-in capital	612,110	552,037
Accumulated other comprehensive loss		(74)
Accumulated deficit	(754,407)	(655,170)
Total stockholders' deficit	(141,146)	(102,140)
Total liabilities, non-controlling interest and stockholders' deficit	$ 102,684	$ 158,656