Summary of Debt (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Equipment note	Dec. 31, 2012 Equipment note	Mar. 31, 2013 Silicon valley bank term loan	Dec. 31, 2012 Silicon valley bank term loan	Mar. 31, 2013 Peoria facility note	Dec. 31, 2012 Peoria facility note	Mar. 31, 2013 HSBC Facility	Mar. 31, 2013 Convertible Senior Subordinated Notes	Jan. 24, 2013 Convertible Senior Subordinated Notes	Mar. 31, 2013 Secured and unsecured debt	Dec. 31, 2012 Secured and unsecured debt
Debt Instrument [Line Items]
Total debt	$ 135,484	$ 14,968	$ 115	$ 129		$ 11,233		$ 3,606	$ 10,369	$ 125,000		$ 10,484	$ 14,968
Initial fair value of embedded derivative	3,124
Change in fair value of embedded derivative	737
Unamortized debt discount	(8,132)										(5,300)
Current portion of debt	(60)	(7,331)
Long-term portion of debt	$ 131,153	$ 7,637
Maturity Date			January 2015		March 2013		February 2013		March 2015	February 2018