Summary of Significant Accounting Policies (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Numerator:
Net loss attributable to common stockholders	$ (6,990)	$ (14,088)
Denominator:
Weighted average common shares	59,270	57,031
Basic loss per share attributable to common stockholders	$ (0.12)	$ (0.25)