Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Allowance for doubtful accounts	$ 472	$ 161
Common stock, par value (per share)	$ 0.001	$ 0.001
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	63,068,463	58,577,484
Common stock, shares outstanding	62,573,763	58,082,784
Treasury stock, shares	494,700	494,700
Convertible Preferred Stock
Convertible preferred stock, par value (per share)	$ 0.001	$ 0.001
Convertible preferred stock, shares authorized	5,000,000	5,000,000
Convertible preferred stock, shares issued	0	0
Convertible preferred stock, shares outstanding	0	0