Condensed Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 47,944	$ 56,537
Short-term investments	11,780	3,525
Prepaid clinical development costs	1,330	196
Other prepaid and current assets	265	362
Total current assets	61,319	60,620
Property and equipment, net	851	81
Intangible assets	56	56
Long-term investments	7,061	17,537
Total assets	69,287	78,294
Current liabilities:
Accounts payable	4,211	2,232
Accrued clinical development costs	360	884
Other accrued liabilities	885	1,087
Total current liabilities	5,456	4,203
Long-term debt, net of discount	4,922
Total liabilities	10,378	4,203
Commitments and contingencies (Note 5)
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized as of June 30, 2014 and December 31, 2013; no shares issued or outstanding at June 30, 2014 and December 31, 2013
Common stock, $0.001 par value; 120,000,000 shares authorized as of June 30, 2014 and December 31, 2013; 15,445,003 shares issued and 15,431,876 outstanding at June 30, 2014 and 15,357,413 shares issued and 15,340,710 outstanding at December 31, 2013	15	15
Additional paid-in capital	144,064	142,142
Accumulated other comprehensive income (loss)	5	(3)
Accumulated deficit	(85,175)	(68,063)
Total stockholders' equity	58,909	74,091
Total liabilities and stockholders' equity	$ 69,287	$ 78,294