Condensed Balance Sheets (Current Period Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Cash and cash equivalents	$ 22,597	$ 53,506
Prepaid expenses and other current assets	763	584
Total current assets	23,360	54,090
Property and equipment, net	2,857	1,752
Other long-term assets	153	130
Total assets	26,370	55,972
Accounts payable	2,250	1,912
Accrued expenses	2,360	1,750
Convertible notes payable to related parties, net of discount	888	492
Total current liabilities	5,498	4,154
Common stock	3,110	3,024
Additional paid-in capital	242,589	232,381
Accumulated deficit	(224,827)	(183,587)
Total stockholders' equity	20,872	51,818
Total liabilities and stockholders' equity	$ 26,370	$ 55,972

Including the current and noncurrent portions, carrying value as of the balance sheet date of a written promise to pay a note, initially due after one year or beyond the operating cycle if longer, which can be exchanged for a specified amount of one or more securities (typically common stock), at the option of the holder.

No definition available.