Convertible preferred stock (Tables)

12 Months Ended

Dec. 31, 2012

Convertible Preferred Stock

Schedule of convertible preferred stock

	Convertible Preferred Stock
	Carrying Value		Shares Outstanding		Liquidation Preference		Conversion Price
Series B	$	14,046		3,874	$	4.40	$	2.85
Series C		24,459		14,424	$	1.89	$	1.89
Series D		28,267		8,086	$	3.50	$	3.50
Series E		64,531		14,991	$	4.50	$	4.50
Series F		59,973		11,776	$	5.10	$	5.10
Series G		76,949		11,000	$	7.00	$	7.00
Balance at December 31, 2011	$	268,225		64,151