Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 120,840	$ 65,726
Restricted cash	911	200
Prepaid expenses and other current assets	1,772	1,505
Total current assets	123,523	67,431
Property and equipment, net	6,534	3,145
Other assets	0	219
Total assets	130,057	70,795
Current liabilities:
Accounts payable	6,239	6,652
Accrued clinical and other expenses	795	1,029
Accrued payroll and related expenses	3,228	2,077
Total current liabilities	10,262	9,758
Shareholders’ equity:
Common Stock, $0.0001 par value; 100,000,000 shares authorized, 22,145,243 and 18,261,557 shares issued and outstanding at September 30, 2017 and December 31, 2016, respectively	2	2
Additional paid-in capital	796,118	661,103
Accumulated deficit	(682,968)	(606,711)
Total shareholders’ equity	119,795	61,037
Total liabilities and shareholders’ equity	130,057	70,795
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