Condensed Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 24,824	$ 18,653
Marketable securities	17,058	4,000
Prepaid expenses and other current assets	1,434	2,463
Total current assets	43,316	25,116
Property and equipment, net	107	139
Other assets	45	45
Total assets	43,468	25,300
Current liabilities:
Accounts payable	1,568	550
Accrued expenses and other current liabilities	20,114	8,740
Current portion of note payable, net of discount	9,876	7,800
Total current liabilities	31,558	17,090
Note payable, net of current portion and discount	7,207	13,005
Warrant liability	1,992	830
Other liabilities	18,225	24,387
Commitments and contingencies
Stockholders' deficit:
Common stock, $.0001 par value; 100,000,000 shares authorized, 879,370 and 867,204 shares issued and outstanding at June 30, 2013 and December 31, 2012, respectively	0	0
Additional paid-in-capital	0
Accumulated other comprehensive income	3
Accumulated deficit	(235,630)	(200,661)
Total stockholders' deficit	(235,627)	(200,661)
Total liabilities, convertible preferred stock and stockholders' deficit	43,468	25,300
Series B Convertible Preferred Stock
Current liabilities:
Preferred Stock	42,155
Stockholders' deficit:
Total stockholders' deficit	42,155
Series A-1 Convertible Preferred Stock
Current liabilities:
Preferred Stock	75,263	71,957
Stockholders' deficit:
Total stockholders' deficit	75,263	71,957
Series A-2 Convertible Preferred Stock
Current liabilities:
Preferred Stock	90,211	86,714
Stockholders' deficit:
Total stockholders' deficit	90,211	86,714
Series A-3 Convertible Preferred Stock
Current liabilities:
Preferred Stock	11,688	11,182
Stockholders' deficit:
Total stockholders' deficit	11,688	11,182
Series A-4 Convertible Preferred Stock
Current liabilities:
Preferred Stock	271	271
Stockholders' deficit:
Total stockholders' deficit	271	271
Series A-5 Convertible Preferred Stock
Current liabilities:
Preferred Stock	525	525
Stockholders' deficit:
Total stockholders' deficit	525	525
Series A-6 Convertible Preferred Stock
Current liabilities:
Preferred Stock	0	0
Stockholders' deficit:
Total stockholders' deficit	$ 0