Consolidated Statements of Comprehensive Loss (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement of Comprehensive Income [Abstract]
Net loss	$ (3,436)	$ (4,971)	$ (7,090)	$ (14,774)
Other comprehensive gain (loss):
Unrealized gain (loss) on investment securities, available-for-sale	0	(2)	0	3
Less: reclassification adjustment for losses realized in net loss	0	32	0	32
Comprehensive loss	$ (3,436)	$ (4,941)	$ (7,090)	$ (14,739)