Basis of Presentation - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013 Agreement Segment	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011	May 07, 2013 Subsequent Event
Basis of Presentation [Line Items]
Number of operating segment	1
Working capital	$ 5,200,000
Cash and cash equivalents	1,229,000	2,543,000	2,772,000	3,307,000
Net accounts receivable	10,644,000	11,680,000
Lines of credit remaining borrowing capacity	4,700,000
Number revolving credit facility agreements	2
Period of financial resources	The working capital and borrowings available under the lines of credit should be sufficient to fund the requirements of the Company.
Lines of credit borrowing capacity	$ 8,000,000				$ 10,000,000