Quarterly Financial Information (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2012

Quarterly Financial Information (Unaudited) [Abstract]

Summary of Quarterly Financial Information

	First			Second			Third			Fourth
2012 Quarters
Revenues	$	12,221		$	4,210		$	5,761		$	4,101
Net Loss		(6,052	)		(12,276	)		(9,700	)		(11,053	)
Basic and diluted net loss per share		(0.13	)		(0.25	)		(0.19	)		(0.22	)
2011 Quarters
Revenues	$	5,435		$	3,735		$	5,249		$	5,224
Net loss		(13,027	)		(16,271	)		(14,459	)		(13,192	)
Basic and diluted net loss per share		(0.29	)		(0.36	)		(0.32	)		(0.29	)