CONDENSED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities:
Net loss	$ (6,171)	$ (6,857)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	96	119
Non-cash charges for stock-based compensation	626	638
Impairment of long lived assets	229	0
Changes in current assets and liabilities, net	(294)	905
Changes in non-current assets, net	(56)	(43)
Net cash used in operating activities	(5,570)	(5,238)
Cash flows from investing activities:
Purchases of property and equipment	(363)	(243)
Purchases of investment securities	(1,977)	(21,443)
Proceeds from sale and maturities of investment securities	9,600	26,884
Net cash provided by investing activities	7,260	5,198
Cash flows from financing activities:	0	0
Increase/(decrease) in cash and cash equivalents	1,690	(40)
Beginning balance of cash and cash equivalents	4,150	4,114
Ending balance of cash and cash equivalents	$ 5,840	$ 4,074