Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 113,071	$ 126,467
Restricted cash	200	237
Prepaid clinical expenses	64	223
Prepaid expenses and other current assets	1,408	618
Total current assets	114,743	127,545
Property and equipment, net	2,047	1,732
Other assets	217	70
Total assets	117,007	129,347
Current liabilities:
Accounts payable	2,408	2,506
Accrued expenses	2,411	1,224
Accrued payroll and related expenses	352	1,090
Total current liabilities	5,171	4,820
Shareholders’ equity:
Common Stock, $0.0001 par value; 100,000,000 shares authorized, 18,254,009 and 18,244,009 shares issued and outstanding at March 31, 2016 and December 31, 2015, respectively	2	2
Additional paid-in capital	650,198	646,408
Accumulated deficit	(545,007)	(528,526)
Total shareholders’ equity	111,836	124,527
Total liabilities and shareholders’ equity	117,007	129,347
Series C-1 Convertible Preferred Stock [Member]
Shareholders’ equity:
Convertible preferred stock, value	3,906	3,906
Series F Convertible Preferred Stock [Member]
Shareholders’ equity:
Convertible preferred stock, value	$ 2,737	$ 2,737