Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 65,726	$ 126,467
Restricted cash	200	237
Prepaid clinical expenses	67	223
Prepaid expenses and other current assets	1,438	618
Total current assets	67,431	127,545
Property and equipment, net	3,145	1,732
Other assets	219	70
Total assets	70,795	129,347
Current liabilities:
Accounts payable	6,652	3,052
Accrued clinical and other expenses	1,029	678
Accrued payroll and related expenses	2,077	1,090
Total current liabilities	9,758	4,820
Commitments and contingencies
Shareholders’ equity:
Common Stock, $0.0001 par value; 100,000,000 shares authorized, 18,261,557 and 18,244,009 shares issued and outstanding at December 31, 2016 and December 31, 2015, respectively	2	2
Additional paid-in capital	661,103	646,408
Accumulated deficit	(606,711)	(528,526)
Total shareholders’ equity	61,037	124,527
Total liabilities and shareholders’ equity	70,795	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