Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]
Property and equipment, accumulated depreciation and amortization	$ 17,173	$ 16,708
Patent costs, accumulated amortization	$ 1,439	$ 2,626
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	32,433,083	31,703,817
Common stock, outstanding	32,433,083	31,703,817