CONDENSED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 32,080	$ 7,726
Contract receivables		108
Accrued interest receivable		9
Prepaid expenses	33	147
Total current assets	32,113	7,990
Property and equipment, net	9	84
Other assets	42	42
Total assets	32,164	8,116
Current liabilities:
Accounts payable	1,039	657
Accrued liabilities	1,204	894
Convertible notes		13,737
Accrued interest payable		2,566
Total current liabilities	2,243	17,854
Convertible notes	4,374
Long term warrant liability	5,310
Deferred rent	131	132
Total Liabilities	12,058	17,986
Commitments and contingencies (Note 8)
Redeemable convertible preferred stock, $0.0001 par value: 55,258,608 shares authorized; 0 and 624,426 shares issued and outstanding as of September 30, 2013 and December 31, 2012, respectively; aggregate liquidation preference of $256,750 as of December 31, 2012		318,697
Stockholders' equity (deficit):
Common stock, $0.0001 par value: 100,000,000 shares authorized; 8,790,764 and 5,792 shares issued and outstanding as of September 30, 2013 and December 31, 2012, respectively	1
Additional paid-in capital	365,033	913
Accumulated other comprehensive income (loss)
Accumulated deficit	(344,928)	(329,480)
Total stockholders' equity (deficit)	20,106	(328,567)
Total liabilities and redeemable convertible preferred stock and stockholders' equity (deficit)	$ 32,164	$ 8,116