Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 65,086	$ 37,714
Available-for-sale securities	90,116	72,238
Restricted cash	101	100
Accounts receivable	5,857	9,267
Prepaid expenses and other current assets	5,484	8,982
Total current assets	166,644	128,301
Restricted cash	584	528
Property and equipment, net	13,364	6,297
Other assets	175	1,068
Intangible assets, net	1,845	2,165
In-process research and development	6,200	7,010
Goodwill	3,605	3,605
Total assets	192,417	148,974
Current liabilities:
Accounts payable, accrued expenses and other	38,814	25,644
Deferred revenues	9,336	9,350
Deferred rent	1,336	1,153
Long-term debt, current portion	8,248	2,373
Total current liabilities	57,734	38,520
Deferred revenues, net of current portion	66,139	71,114
Deferred rent, net of current portion	6,538	6,323
Deferred tax incentives, net of current portion	507	755
Long-term debt, net of current portion	103,427	37,482
Accrued interest	1,200	1,200
Total liabilities	235,545	155,394
Commitments and contingencies (Note 16)
Non-controlling interest	337	97
Stockholders' deficit:
Preferred stock, $0.01 par value: 10,000 shares authorized at December 31, 2013 and 2012, respectively; no shares issued or outstanding at December 31, 2013 or 2012
Common stock, $0.01 par value: 200,000 shares authorized at December 31, 2013 and 2012, respectively, 102,523 and 95,825 issued and outstanding at December 31, 2013 and 2012, respectively	1,025	958
Additional paid-in capital	527,779	434,679
Accumulated other comprehensive loss	(24)	(38)
Accumulated deficit	(572,245)	(442,116)
Total stockholders' deficit	(43,465)	(6,517)
Total liabilities, non-controlling interest and stockholders' deficit	$ 192,417	$ 148,974