Condensed Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 42,712	$ 48,555
Restricted cash	37	37
Prepaid clinical expenses	1,449	1,528
Prepaid expenses and other current assets	622	137
Total current assets	44,820	50,257
Equipment and furnishings, net	659	279
Other assets	57	0
Total assets	45,536	50,536
Current liabilities:
Accounts payable	2,459	730
Accrued expenses	117	926
Accrued payroll and related expenses	0	424
Total current liabilities	2,576	2,080
Shareholders’ equity:
Common Stock, $0.0001 par value; 100,000,000 shares authorized, 15,250,840 and 15,225,980 shares issued and outstanding at March 31, 2015 and December 31, 2014, respectively	2	2
Additional paid-in capital	531,873	528,353
Accumulated deficit	(495,569)	(486,614)
Total shareholders’ equity	42,960	48,456
Total liabilities and shareholders' equity	45,536	50,536
Series C-1 Convertible Preferred Stock [Member]
Shareholders’ equity:
Convertible preferred stock, value	3,917	3,917
Series F Convertible Preferred Stock [Member]
Shareholders’ equity:
Convertible preferred stock, value	$ 2,737	$ 2,798