Debt (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Total debt, Principal	$ 7,773	$ 7,300
Total debt, Unamortized amount	(49)	(84)
Total debt	7,724	7,216
Less: debt - current, Principal	(4,857)	(2,554)
Less: debt - current, Unamortized Discount	29	35
Less: debt - current	(4,828)	(2,519)
Debt - non-current, Principal	2,916	4,746
Debt - non-current, Unamortized Discount	(20)	(49)
Debt - non-current	2,896	4,697
Comerica - Growth Capital Loan A, due 2015
Debt Instrument [Line Items]
Total debt, Principal	4,583	5,000
Total debt, Unamortized amount	(49)	(84)
Total debt	4,534	4,916
Comerica - Revolving Line of Credit, due 2014
Debt Instrument [Line Items]
Total debt, Principal	3,190	2,300
Total debt, Unamortized amount	0	0
Total debt	$ 3,190	$ 2,300