CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current Assets:
Cash and cash equivalents	$ 20,635	$ 18,130
Available-for-sale securities	50,003	50,027
Prepaid expenses and other current assets	5,578	3,718
Total Current Assets	76,216	71,875
Property and equipment, net	589	589
Security deposits	94	94
Total Assets	76,899	72,558
Current Liabilities:
Accounts payable	9,931	13,542
Accrued expenses	2,663	2,134
Total Current Liabilities	12,594	15,676
Derivative financial instruments, at estimated fair value-warrants	1,311	1,534
Total Liabilities	13,905	17,210
Stockholders' Equity:
Preferred stock, Authorized 20,000,000 shares, at March 31, 2014 and December 31, 2013, none outstanding
Common stock, par value of $.0001 authorized 200,000,000 shares at March 31, 2014 and 200,000,000 shares at December 31, 2013. Issued and outstanding 94,064,506 and 90,182,115 shares at March 31, 2014 and December 31, 2013 respectively.	10	10
Additional paid-in capital	250,386	226,515
Deficit accumulated during development stage	(187,402)	(171,177)
Total Stockholders' Equity	62,994	55,348
Total Liabilities and Stockholders' Equity	$ 76,899	$ 72,558