Customer Deposits - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Deposit Liabilities [Line Items]
Customer deposits	$ 746	$ 1,402
Sales contract payment terms advance percentage payable	30.00%
Sales contract payment terms freight on road percentage payable	60.00%
Sales contract payment terms customer acceptance percentage payable	10.00%
Nuclear Pharm Assist Systems
Deposit Liabilities [Line Items]
Customer deposits	669	669
Number of systems, orders placed	5
Attrius Pet systems
Deposit Liabilities [Line Items]
Customer deposits	$ 77	$ 733
Number of systems, orders placed		2
Number of used machines, orders placed	2	2