Summary of Debt (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Total debt	$ 14,968	$ 20,252
Less: current portion of debt	(7,331)	(5,289)
Total long-term debt	7,637	14,963
Peoria Facility note, due 2013
Debt Instrument [Line Items]
Total debt	3,606	5,357
Equipment note, due 2015
Debt Instrument [Line Items]
Total debt	129	179
Silicon Valley Bank note, due 2015
Debt Instrument [Line Items]
Total debt	$ 11,233	$ 14,716