Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Property and equipment, accumulated depreciation and amortization	$ 16,708	$ 15,765
Patent costs, accumulated amortization	$ 2,626	$ 2,199
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	3,333,333	3,333,333
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	50,000,000	50,000,000
Common stock, issued	31,703,817	22,623,853
Common stock, outstanding	31,703,817	22,623,853