Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 105,451	$ 37,714
Available-for-sale securities	77,034	72,238
Restricted cash	101	100
Accounts receivable	8,835	9,267
Prepaid expenses and other current assets	8,860	8,982
Total current assets	200,281	128,301
Restricted cash	583	528
Property and equipment, net	11,468	6,297
Other assets	181	1,068
Intangible assets, net	1,925	2,165
In-process research and development	6,200	7,010
Goodwill	3,605	3,605
Total assets	224,243	148,974
Current liabilities:
Accounts payable, accrued expenses and other	42,913	24,936
Deferred revenues	9,336	9,350
Loans payable	6,376	2,373
Other current liabilities	2,234	1,861
Total current liabilities	60,859	38,520
Deferred revenues, net of current portion	66,390	71,114
Loans payable, net of current portion	34,379	37,482
Accrued interest, net of current portion	1,200	1,200
Other long-term liabilities	7,476	7,078
4.50% convertible senior notes	70,574
Total liabilities	240,878	155,394
Commitments and contingencies (Note 10)
Non-controlling interest (deficit)	(374)	97
Stockholders' deficit:
Preferred stock, $0.01 par value: 10,000 shares authorized at December 31, 2012 and September 30, 2013; no shares issued or outstanding at December 31, 2012 and September 30, 2013
Common stock, $0.01 par value: 200,000 shares authorized at December 31, 2012 and September 30, 2013; 95,825 and 102,275 shares issued and outstanding at December 31, 2012 and September 30, 2013, respectively	1,023	958
Additional paid-in capital	522,714	434,679
Accumulated other comprehensive loss	(16)	(38)
Accumulated deficit	(539,982)	(442,116)
Total stockholders' deficit	(16,261)	(6,517)
Total liabilities, non-controlling interest (deficit) and stockholders' deficit	$ 224,243	$ 148,974