Balance Sheets (USD $)	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 18,653,000	$ 25,128,000
Marketable securities	4,000,000	31,580,000
Prepaid expenses and other current assets	2,463,000	6,682,000
Total current assets	25,116,000	63,390,000
Property and equipment, net	139,000	167,000
Other assets	45,000	80,000
Total assets	25,300,000	63,637,000
Current liabilities:
Accounts payable	550,000	313,000
Accrued expenses and other current liabilities	8,740,000	3,590,000
Current portion of note payable, net of discount	7,800,000	2,880,000
Total current liabilities	17,090,000	6,783,000
Note payable, net of current portion and discount	13,005,000	8,886,000
Warrant liability	830,000	450,000
Other liabilities	24,387,000	10,470,000
Commitments and contingencies (Note 17)
Stockholders' deficit:
Common stock, $.0001 par value; 100,000,000 shares authorized, 867,204 and 645,399 shares issued and outstanding at December 31, 2012 and December 31, 2011, respectively
Additional paid-in-capital		2,744,000
Accumulated other comprehensive loss		5,000
Accumulated deficit	(200,661,000)	(122,359,000)
Total stockholders' deficit	(200,661,000)	(119,610,000)
Total liabilities, convertible preferred stock, redeemable convertible preferred stock and stockholders' deficit	25,300,000	63,637,000
Series A-1 Convertible Preferred Stock
Current liabilities:
Preferred Stock	71,957,000	65,675,000
Stockholders' deficit:
Total stockholders' deficit	71,957,000	65,675,000
Series A-2 Convertible Preferred Stock
Current liabilities:
Preferred Stock	86,714,000	79,979,000
Stockholders' deficit:
Total stockholders' deficit	86,714,000	79,979,000
Series A-3 Convertible Preferred Stock
Current liabilities:
Preferred Stock	11,182,000	10,208,000
Stockholders' deficit:
Total stockholders' deficit	11,182,000	10,208,000
Series A-4 Convertible Preferred Stock
Current liabilities:
Preferred Stock	271,000	271,000
Stockholders' deficit:
Total stockholders' deficit	271,000	271,000
Series A-5 Convertible Preferred Stock
Current liabilities:
Preferred Stock	525,000	525,000
Stockholders' deficit:
Total stockholders' deficit	525,000	525,000
Series A-6 Convertible Preferred Stock
Current liabilities:
Preferred Stock