Accounts Payable and Accrued Liabilities - Accounts Payable and Accrued Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Payables And Accruals [Abstract]
Accounts payable	$ 2,779	$ 2,797
Accrued liabilities:
Employee benefits	3,228	6,541
Taxes other than on income	483	439
Customer tooling	341	282
Insurance	257	305
Professional	221	189
Other	620	508
Total accounts payable and accrued liabilities	$ 7,929	$ 11,061