Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 10,923	$ 54,220
Marketable securities	29,790	22,511
Contract receivables		44
Prepaid expenses and other current assets	1,532	742
Restricted cash		205
Total current assets	42,245	77,722
Restricted cash	193
Property and equipment, net	414	276
Other assets	125	706
Total assets	42,977	78,704
Current liabilities:
Accounts payable	1,822	3,197
Accrued compensation	1,400	1,091
Deferred rent, short-term	16	160
Accrued research and clinical liabilities	3,470	3,309
Notes payable, short-term	10,928	3,182
Financing derivative	89
Other accrued liabilities	328	443
Total current liabilities	18,053	11,382
Deferred rent, long-term	311
Notes payable, long-term		6,786
Total liabilities	18,364	18,168
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value: 85,000,000 shares and 47,500,000 shares authorized at December 31, 2014 and December 31, 2013 respectively; 32,922,178 and 32,922,178 shares issued and outstanding at December 31, 2014 and December 31, 2013 respectively	33	33
Additional paid-in capital	202,801	200,715
Accumulated other comprehensive income	(8)	3
Accumulated deficit	(178,213)	(140,215)
Total stockholders’ equity	24,613	60,536
Total liabilities and stockholders’ equity	$ 42,977	$ 78,704