Accrued Expenses and Other Current Liabilities (Details) - Accrued expenses and other current liabilities (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Accrued expenses and other current liabilities [Abstract]
Accrued salaries and benefits	$ 1,089	$ 1,232
Warrant liability	485	939
Liability for consigned precious metals	654	832
Accrued legal settlement and related expenses	783	616
Accrued severance and other charges	371	530
Accrued warranty	458	453	824	665
Other	1,594	1,400
Accrued expenses and other current liabilities	$ 5,434	$ 6,002