Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	23,000,000
Common stock, shares issued	14,268,068	3,529,406
Common stock, shares outstanding	12,622,919	1,209,752
Series A convertible preferred stock
Convertible preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Convertible preferred stock, shares authorized	0	6,200,000
Convertible preferred stock, shares issued	0	6,200,000
Convertible preferred stock, shares outstanding	0	6,200,000
Convertible preferred stock, liquidation preference (in dollars)		$ 6,200